For some RVing or OHVing is a hobby all by itself. For others, especially those who may be full-timers or spend significant time in their RV each year, they have other hobbies they may want to bring along. For some an RV is the means to get where they're going to exercise their hobby. RVs make good base camps for hiking, fishing, hunting, birdwatching, sight seeing, OHV riding, horseback riding, and rock collecting.
What hobbies can you bring along? You are really only limited by your imagination and how much specialized equipment your hobby requires -- and how much room you have to haul it. Some typical things people bring along include various kinds of sewing or needlework, jewelry making, music (especially portable instruments like guitars, banjos, and harmonicas), and wood carving. If your hobby is furniture making you may need an equipment trailer to serve as your shop and haul the lathes and other power equipment you use. I have seen a few RV parks that cater to woodworkers and, over time, customers have built up a pretty complete workshop. Things like stamp and coin collecting take up little room in an RV. I would be a little concerned about security for high-dollar hobbies like these. In the first place, I would minimize the exposure by not openly advertising my collection (security by obscurity). Next I would invest in a quality floor safe to house my valuables, install an alarm system, and be sure to lock up whenever I have to leave my RV.
Some resorts and other destinations cater to specific hobbies. The annual winter encampment at Quartzite, Arizona, is a jewelry and rock hound heaven. I have read of resorts that have wood shops with equipment donated by customers or acquired through fund raising by selling products created there by clients during their stay. Some resorts support various sports and games, like golf, shuffleboard, and pickleball by providing facilities and even sponsoring tournaments. We had a small archery range at the resort where I worked as assistant manager a couple of summers ago. Some locations may serve as a base camp for OHV trails.
Crafts of various kinds are popular pastimes for campers. Because many crafts, like jewelry making and various kinds of needlework, require little in the way of bulky materials or tools, they lend themselves well to to semi-nomadic lifestyle of campers. You might even find a market for your wares within campgrounds.
Music is a common hobby among RVers. You will mostly find campfire compatible instruments like guitars, banjos, harmonicas, and tambourines but I've seen at least one couple that also brought along a bass fiddle to entertain their fellow campers. Folk music and bluegrass music seem to most popular, with country music close behind, followed by pop music. There are even special "break-away" guitars that fold up to be more compact for RV travel. Or get a Martin "Backpacker" guitar. The Backpacker is very compact but it doesn't have a lot of volume. It is a nice option to entertain yourself in your tent, but probably not loud enough for a sing-a-long around the campfire. Brass instruments and electric guitars aren't very common in campgrounds. Synthesizers offer an abundance of sounds if you prefer keyboards and can sometimes be quite compact and easy to transport. You will probably need a campground with electrical hookups or a generator to power them.
For some collectors, RV trips are hunting expeditions. Since you are often traveling outside your normal stomping grounds you have a chance to seek out bargains in places off the beaten path. That works pretty well for small collectibles like stamps, coins, dolls, books, records, etc., but you'll need to pull a big trailer if you're hunting for furniture or other large antiques. Or come back for them or pay to have them shipped. Sometimes it is cheaper and a lot more convenient to bring a rental truck back than to pull a big trailer all over creation and half of Georgia! Some people may be tempted to use their RV roof as a cargo area. This is generally not a good idea, especially for large or heavy items. The risk of injury to people or damage to the items or the RV while loading or unloading is too great. Carrying heavy items on the roof may damage the roof and could affect handling. Having items exposed to the elements and sticking up where they might get caught on limbs or other low hanging obstacles is also a recipe for trouble. It is amazing what people collect these days. Old school lunch boxes, cereal boxes, dolls, toys, clocks, bottle-caps; you name it! If you have an interest in and knowledge of such items you may be able to find good deals on salable items as you travel. Some people put their finds on ebay immediately and sell them while they're still on the road, sometimes paying for their trip and even turning a profit. You may even be able to write off some of your travels on your taxes if your trip is a legitimate expedition to search for merchandise or buyers.
Camping itself is a hobby for some people. Collecting and trying out new camping gadgets is always fun to do. Scouring local stores or even garage sales for unusual camping items or bargains can be very exciting and rewarding. Talking with rangers, camp hosts, and fellow campers enhances your knowledge of the area and adds to your camping skills. There are lots of opportunities for creative camp cooking.
For some people shopping and bargain hunting is a hobby. The proliferation of "Factory Outlet" shopping centers near freeway off ramps attests to the popularity of bargain hunting. Many advertise having RV parking. Many times you will find special deals on clothing, household goods, tools, and camping gear. There was an auto parts store near my parents' house that I liked to check out whenever we went for a visit. I usually found some new hand tools at better prices than I ever saw at home. Don't know what their secret was. It was a small town so I'm pretty sure they weren't fencing stolen goods! Which brings up another consideration: if something seems too good to be true, it usually is! If someone offers you something like a Rolex watch for $50 you can be sure it is either a fake, it is broken, or it is stolen! Caveat emptor! But there are rare exceptions. Like a man who saw a late model Cadillac advertised in newspaper classifieds for just $50. Since the asking price was way below even the salvage value that a junk yard would pay he was very skeptical but finally decided to check it out anyway. He found the vehicle was in like-new condition, with no hidden history, accident damage, liens, or being a murder site or anything nasty like that. It was clearly worth thousands of dollars. Because so many people were skeptical or believed the price to be a misprint, he was the only one that showed up to actually look at the car. Turns out the car had belonged to the woman's late husband, who, in his will, had directed that it be sold and the proceeds given to his mistress! The savvy and understandably unhappy wife cleverly found a way to comply with his request without giving much of anything to the mistress.
Some people have hobbies they like to take with them when camping. As you might expect, some hobbies lend themselves to being incorporated into camping activities more than others, although you might be surprised at some of the options. For example, woodworking usually requires a lot of special tools and a considerable amount of specialized equipment and plenty of room to work. While those requirements are rather difficult to include in your personal RV, I have read of campgrounds that cater to woodworkers and have a fairly well equipped shop available for their use with machines donated by or purchased by regular users. However most people who take their hobbies on the road with them choose activities that are pretty much self contained and for which all the necessary supplies and equipment can be conveniently pack in the RV. Musicians take their portable instruments. Most kinds of needle work can be fairly easily adapted for camping. Scrapbooking is popular among some people. Stamp collecting and coin collecting can be accommodated, but because these sometimes involve high value items you may need extra security, such as a safe.
If you are going to take your hobby on the road with you, think about what special features, supplies, and equipment you may need. If you need computer access for research, inventory, or bookkeeping, do you have an appropriate place in your RV to set up a work station? If you need a place to examine items, do you have appropriate work space and adequate lighting? If you need any special tools do you have them and have an appropriate and convenient place to put them in your RV? If you find you are deficient in any way, it might be a good idea to wait until you have things ready before you hit the road. With a little creativity you can usually adapt your RV to accommodate your needs.
Some hobbies can also be a revenue source for RVers. I've seen RVers sell hand made craft items and others who shop garage sales, flea markets, and 2nd hand stores for collectibles they can resell on ebay. Reselling right away on ebay avoids the need to haul stuff around as you can usually package it up and send it via UPS or the USPS from almost anywhere.
Sometimes an RV can be a hobby of its own. Certain traditional brands, like Airstream and Shasta, even have large owner clubs who foster sharing information and activities. But even an "ordinary" RV can be a hobby to some owners -- customizing it, using it, improving it, showing it off.
Hobbies are fun!