Drill a 4-inch-diameter hole into the floor of the trailer at each corner of the trailer using the drill and 4-inch-circle cutting drill bit.
Stand one, 4-feet-long, 4-inch-diameter PVC pipe into each of the holes that you just cut. Then secure them into place by placing epoxy glue around each one thus gluing each one to the wood flat deck of the utility trailer. These will form the corners of the rectangle box that will be the sleeping enclosure of the trailer.
Glue a 3-point PVC pipe corner connection piece on top of each of the 4-feet-long, 4-inch-diameter PVC pipes. This should be done where there is a 90 degree angle on top of each pipe with each end of the angle pointing to the pipes coming up on the trailer's corners next to each pipe so that when the other pipes are placed a rectangle will be formed above the floor of the trailer.
Glue the remaining two, 4-feet-long PVC pipes into the 3-point PVC pipe corner connection pieces to where the 4-feet pipes are parallel to the front and rear edge of the floor of the trailer. These will be the ends of the rectangle sleeping enclosure box.
Glue the two, 8-feet-long PVC pipes into the 3-point PVC pipe corner connection pieces to where the 8-feet pipes are parallel to the side edges of the floor of the trailer. These will form the sides of the rectangle sleeping enclosure box. There is now a rectangle-shaped PVC box that is over the floor of the trailer. Once the plastic sheets are in place the sleeping enclosure box will be made.
Screw the 4-feet-wide-by-4-feet-long, ½-inch-thick plastic sheets to the rectangle shaped PVC pipe box on the front and rear ends of the trailer. Use the drill, screwdriver bit, and 2-inch long screws to do this. This will close the front and rear sides of the sleeping enclosure.
Screw two of the 4-feet-wide-by-8-feet-long, ½-inch thick plastic sheets to the two sides of the PVC pipe box by screwing the 4-feet-long ends of the plastic sheet to the 4-feet-long corner pipes. Then along the 8-feet-long top side screw the plastic sheet to the 8-feet-long PVC pipe. Use the drill, screwdriver bit and 2-inch-long screws to do this. This will close the left and right sides of the sleeping enclosure.
Place the remaining 4-feet-wide-by-8-feet-long, ½-inch thick plastic sheet on the top of the PVC pipe box and secure it to the box using the 2-inch screws. The sleeping enclosure is now built.
Put the caulk into the caulk gun. Then open the end of the caulk tube. Now shoot caulk into all seams on the sleeping enclosure box. This will seal the box up for being water tight to keep rain out of the sleeping area. The next part of the project involves cutting a door into the side of the sleeping enclosure for access and fitting the hinges and latches for the door and then placing the mattress.
Measure and mark a 3 1/2-feet-long horizontal line 6 inches down from the top of the sleeping enclosure on one side of the trailer just behind the wheel of the trailer.
Measure and mark a 3 1/2-feet-long horizontal line 6 inches up from the bottom of the sleeping enclosure just behind the wheel of the trailer on the same side that you marked the line in step 1. Make sure that this line is parallel to the line you made in step 1.
Connect the lines drawn in steps 1 and 2 on their ends with parallel lines that are 3½ feet apart from each other thus drawing a 3½ feet wide by 3-feet-high rectangle on the side of the trailer's sleeping enclosure. This will form the door of the trailer.
Drill a ½-inch hole on one corner of the box. Use the 1/2-inch drill bit to do this.
Slide the blade of the jigsaw through the hole cut in step 4. Then proceed to follow the lines of the box and cut the 3½ feet wide by 3-feet-high rectangle from the side of the trailer's sleeping enclosure. Save this piece that you cut out as this will be the door to the sleeping enclosure.
Glue the rubber weather stripping all around the edges of the 3½-feet-wide-by-3-feet-high hole that is now in the side of the trailer. This is needed to make the door area weatherproof.
Fasten the door hinges to the left side of the 3½-feet-wide-by-3-feet-high hole. Then fasten the hinges to the door piece that you cut out in step 5. Fasten the door hinges along one of the 3-feet-long sides of the door piece so that it will fit snugly over the hole when closed.
Place one of the door latches on the inside of the door. Then place its lock receiver on the inside wall of the trailer's sleeping enclosure to where the door is shut. The latch can be placed over the lock receiver and the lock placed into it to lock the door.
Place one of the door latches on the outside of the door. Place its lock receiver on the outside wall of the trailer's sleeping enclosure to where the door is shut. The latch can be placed over the lock receiver and the lock placed into it to lock the door.
Lay the futon mattress on the floor of the sleeping enclosure and with the 4-feet-wide side up against either the front or back wall and the 6-feet-long side out on the floor. The remaining 2-feet area of the sleeping enclosure at the end of the mattress can be used for the place to pack your other camping gear such as tables and chairs.
Close the door and the door latch over the outside lock receiver. Put the master lock through the lock receiver and lock the door. This is done so that the trailer door will not come open while traveling. The trailer is ready for use at this point.
