Hello, I did a similar build off a ford pickup

bed frame from a totaled pickup truck many years ago. I agree with the another

poster Putting the door in the back makes the air flow while towing a null

concern. You can also then make the deck larger and fold-up able and lockable

while traveling. I also used a folding down bed as a seating area during the

day and a bed at night as some tow-a-longs do presently. Put it long way in the

wagon instead of across that way there is no need to elevate it. With the solar

panels idea, a battery and a New wave oven and say New wave PIC and a small

sink you should be really comfortable.