A truck camper or van would both work, depending on the van. I lived several years out of various full size pickups with shells (not an actual camper) with beds built in them, then a Toyota pickup, then Nissan extra-cab pickup, then to Suburbans, but my vehicle nomadics were over by then. I did primarily National Forest boondocking as its called today, back then i just went and looked for good places to go that didnt have anyone around, though Id sometimes stay closer to town for easy overnighters if I had stuff going on in town. I was primarily around Flagstaff and surrounding areas depending on time of year and some trips in the rockies, 3 times to Alaska. 4wheel drive is nice, and allows you to get in or out of places you may not otherwise, but I rarely actually needed to put it in 4wd unless snow or mud was an issue. Good heavy duty real tire chains can add a huge amount of capability in some of those circumstances as well to a 2wd vehicle and are good even with a 4wd in some places.
My current 2wd 4runner is a good vehicle, plenty of room, and capable of going most places full size rigs can go, even with mine being 2wd. I may get a 4wd version later, but its been very good, I have room to sleep in the back with having the dog and lotsa junk with the dog/cargo platform I made. It gets about 22 mpg on the road, way better than the Suburbans and full size 4x pickups. I doubt id ever get another pickup unless I had to haul a camper, a Suburban or tahoe for towing something larger than my 4runner can tow is about the only things id change to at this point. My plan is a cargo trailer camper in the future when i can go semi-nomadic again, at least seasonally. I dont know yet how big and how much vehicle Ill need, the 4runner is fine for now and short overnights and such arent a problem space wise. If it will do what I need later, that would be great.