Many of our recreational vehicles and vessels have a dinette that provides a comfortable place to sit for meals. Most of these dinettes are also designed so they can be made down into beds. Typically, the table is dropped down so it rests between the facing seats and the back rests are brought down to fill in between the seat cushions. Dinettes made down into beds are usually about the size of a twin bed (36" wide) but may be as large a full size bed (54" wide). Lengths may be a few inches shorter than equivalent household mattresses. Many dinettes are intended for use by children although smaller adults may also find them acceptable. I am about 5'7", my wife about 5'4", and we've always fit comfortably on dinettes made down into beds. The dinette in cab over truck campers is often more accessible and less confining than the large cab over bed. At least you can sit up without bumping your head!
Dinettes usually have storage underneath the seats. Sometimes it can be accessed via doors or drawers on the aisle side of the seat. Other times it is only accessed by lifting the seat. If you have to lift the seat to gain access there is usually a finger hole in the plywood base under the cushion you can use to lift the lid. In one RV I found room under the dinette seat to install an ice chest. It was a good place to carry extra cold drinks for summer trips. If you choose to do something like this, make sure you an still get the ice chest in and out easily enough to drain it after each trip. Or plan on sucking up the water from the melted ice and drying it out after each outing to avoid a nasty mildewed mess.
Dinette upholstery is usually made of rather sturdy materials that will last a long time. It often comes from the factory with a Scothgard treatment on fabric seats to reduce staining and make it easier to clean If yours is not Scotchgard protected you can purchase Scotchgard in an aerosol can and spray your seats for extra protection. Vinyl seats don't need Scotchgard. If the upholstery is getting worn or is out dated or you just don't like the way it looks you can have it reupholstered or recover the cushions yourself. Since the cushions are easily removable you can usually just take them out for re-upholstery (unlike sofas, part of which usually can't be removed). Reupholstering cushions in your boat, camper, or RV is a fairly inexpensive improvement that increases comfort and enjoyment, may extend the useable lifetime of a unit, and might even increase resale value.
Another option for worn out cushions is to replace them with used cushions from another vehicle. Cushions from the same make, model, and year will be most likely to fit properly but often you can simply measure your cushions and find others that will fit close enough, giving you far more options. Some good online places to look are ebay.com and craigslist.org.
In a worst case scenario you can make new cushions or have them made. You just need to get the proper measurements. Many times you can use the old cushions as a pattern but if they are gone or too badly damaged, measure where they go and purchase foam pads to fit and then cover them or have them covered. When choosing new material for your cushions, look for sturdy material that will hold up in regular use. If it doesn't come with a fabric protector, spray it with Scotchgard to reduce soiling and make it easier to clean. You may want to color match the new fabric to coordinate with other furniture or you might want to change the color just for fun. When choosing a new material you might want to consider vinyl if you have small children. It doesn't absorb spills and is easy to clean. For a more comfortable bed, or just seating without the sweat vinyl can induce, go for a nice, sturdy, coarse weave fabric. While some heavy canvas and nylon materials may be suitable you will usually get the best results using fabric designed for upholstery use.
Sometimes you can borrow the cushions from you dinette and use them on benches outside to make sitting outdoors more comfortable. If you choose to do this, take care to keep them out of the dirt and away from campfires and made sure they get back where they belong when you are finished.
Sit this one out!