you guys would be surprised how far you can take a normal travel trailer into no where. When my Father and I go traveling we always find the "off the beaten path roads" which generally mean if we are lucky there might be gravel tracks for a road but generally its just grass and whatever the natural terrain is with out it being a true off road experience. We found one road out in South Dakota that was right on the state line because we crossed in and out of Wyoming and South Dakota 3 or 4 times. The "road" was narry bumpy and in poor condition and eventually led to a one of the fire look out towers. The guy had a 25'-30' travel trailer that he and his wife lived out of while they stayed out at the tower. He told us that he'd been on a lot worse roads than the one we just went. Just proves if you know what you're doing you don't have to spend the extra money to get a "off road camper" unless you really plan on doing stuff where 4 wheel drive is a must...even then there are many stories of people taking 2 wheel drive vehicles into what is considered 4 wheel drive only and out performing their 4wd counter parts.
As far as the shower option. Some campers have an outside shower so as long as you don't mind taking a shower outside you can just convert the inside shower into storage.
Also a generator is a great thing to have if you really plan on roughing it in the middle of no where. For regular camping @ camp grounds with full utilities its not really needed. In all the years we traveled we really only needed one once that I can remember.
Tie down straps are a must. When the wind gets to blowing if your awning is out it can, and has, bent the awning rods or even blown the awning off the sides of trailers. Get the corkscrew ones for the strap you throw across the length of the awning and normal straight in stakes for securing the detachable arms of it.
obviously non perishable food, water, and water purification devices/tablets what have you
if you plan on living off battery power a lot it might be a good idea to check into how much it would cost you to replace all the light bulbs in the trailer with LED lights since they use considerably less power and create little to no heat. At current prices this will cost a decent amount though