Right, the Class B is a van, so you can use it for getting around if necessary. But what are some of the pluses/minuses for trailer vs A and C options? I know my neighbors have a Class C and they tow a car behind. And
@Ted has his method. But what's the tradeoff for driving an RV and towing a car vs driving a truck and towing a trailer? I'm completely unfamiliar with either.
Honestly it depends completely on what you want out of your RVing experience.
For us, we like driving our house down the road. That's why I have a perfectly good pretty new 1-ton diesel truck that is exactly the sort of thing you see towing giant 5th wheels and we went out and bought a 20 (now 22) year old bus. Then when we get where we're going, the Land Rover is much easier to park than a big pickup and still hauls all 5 of us (oh yeah, I had to buy the Land Rover, too, since we didn't own it before the RV).
If you like driving your house down the road, an RV (Class A/B/C) is what you want over a trailer. But if you have a trailer, you just unhook your tow vehicle when you get where you're going and you drive that. If you like not having to own more vehicles, then a trailer is nice because your pickup or other tow vehicle can double as your normal daily driver (I see this a lot, especially with F-150 Ecoboosts). The only downside is that you don't have the comforts of home while you're driving and have to stop to get in/out of the trailer.
The nice part about a Class B is that it's small enough that you can park it in normal parking spots, and thus you don't need a second vehicle (or the size of a trailer) while traveling at all. The problem is that it's a van and therefore the amount of space you have for everything (such as a kitchen/bathroom/shower) gets really cramped, really fast.
Incidentally, we thought "No boondocking" when we first bought our RV. Boondocking has become our favorite way to camp with the RV and we find gets us to the best and most scenic spots. And even if boon docking still ends up not being something you like, when you're on the way to places you'll end up wanting to stop somewhere that's not a campground. Rest area, Walmart parking lot, things like that. Really none of this is a big deal and you're not going to have many creature comforts in a Class B anyway. But you will want at least one house battery that's isolated from the engine battery so that you don't run it dead.
I'm not sure what year range you're looking at on the Ram vans, but the Ram Promasters don't seem to be very good. Friends of ours bought one, lemon lawed it (transmission issues), and the second one had the exact same issues. I couldn't recommend one. It seems the Ford Transits and the Freightliner/Mercedes Sprinters are better.