Wanna hear,
There are a lot of 'ifs' associated with selecting a long term camping/traveling motational device.
If you want to be successful at this, buy the largest truck you can afford.
If you are going to be on pavement with a tiny bit of level dirt or gravel, then you don't need 4WD.
If you are going to travel in the North country during winter, then you may want to have 4WD, or at least good set of chains for dually drive wheels on a 2WD.
If you are a seasoned tent camper at heart, then a smaller domicile will suffice because it will feel like a huge upgrade. It's all perspective.
If you are going to be out a long time or even full time, then you want the largest rig you can afford. The longer time you are out the larger living space you will want. This is what BKA full times in: F-550/huge Lance camper/4WD/winch/trailer with other motational devices/tremendous amount of solar with storage batteries.
If you and yours are young, and have NO claustrophobia, you can get by with smaller. Do not discount this possible snag.
If you plan on boondocking a lot, both urban and rural, make your choice the most innocuous looking, blend in with the scene rig you can.
If traveling/camping in dead of Winter, make sure you have the most insulation possible in said rig.
If away from cities, you want larger tanks that will sustain you for a week or two.
I'm with Brad on the choice of a class C for you. A 24-26 foot class C dually 350-450 with a Ford 350-450, V-10 gas, and the best approach angle/breakover angle/departure angle with an upgrade locking rear differential should get you where you want to go in style and without breaking the bank.
Another option is to buy a used truck and camper combo already as a unit. Minimum 350/3500, dually, gas or diesel. You may have to cast your net far and wide to get the right rig. They are around and more than a few folks on this forum have gone that route. The "debugging" process has already been made.
We've camped/stealth camped hundreds of nights in our tiny, 20 year old 8'6" Lance; it's like an old shoe, and I still go looking to get way out in the rough with our smallest, narrowest, least tall camper where you are on your own with ever possible need for self extraction; so there is no reason for us to upgrade to a Class C or MoHo.
My last advice (worth what you paid for it) is to take a bonafide RV guru with you when inspecting possible buys. He/She will find the flaws and be able to negotiate the price down for you.
