Get a vehicle large enough to use for an RV. You want a large van, possibly as big as a Chevy Express or Dodge Sprinter. You could also look for a small, old school or city bus.
Remove the seats from the vehicle, except for the front ones. This can take some time with the large number of seats on a bus. You may be able to keep a handful of the bus seats installed if they will work with some areas of the RV, like the dining room.
Choose a place in the vehicle to place a bed or two. The area right behind the front seats may be best. You could construct a whole wooden bed frame, bolt and secure it in the vehicle and add mattresses, but stacking sleeping bags on foam cushions can work just as well.
Build a kitchen with small cooking appliances like a camping stove, toaster oven and a microwave. Secure a table to the vehicle wall; the stove goes on top with its propane tank underneath, the microwave goes under the table also, and the oven goes wherever there is room. The kitchen must be near the back door or someplace where there is open air.
Construct a kitchen sink by attaching a smaller table near the kitchen table, cutting a hole in it and placing a stainless steel bowl within the hole. Install a pump and drain system under the sink table if you have the plumbing know-how, or simply store water jugs under the table to pour it into the bowl, then remove the bowl and dispose of the water outside.
Add a dining area if there is plenty of extra room in the vehicle, particularly near the kitchen. You'll need to bolt and secure a table to one wall and chairs to the floor up near the table. If you are using a bus, leaving one set of seats installed and placing the table near them will work.
Install a restroom only if you have plumbing knowledge. This involves more than installing a toilet inside the vehicle with an attached septic tank on the outside. You will also want to enclose the area by constructing walls. Knowing the location of facilities along your travels may be easier.
Create an entertainment and media center. Build or purchase cabinets that will store devices like a TV, DVD player, game console and stereo and install these on one of the walls. Spots near the bed or dining area may be the best location.
Make sure all the devices inside have power. Store three or four deep cycle batteries and connect them to power inverters with standard power cord sockets. Build and install boxes that you can store the batteries and access the inverter sockets, particularly around the kitchen and media center. You can also include a generator, provided you use it outside with extension cords.
