There were a few RT 190's made on the 19' Chevy G-30, but in the age range you're talking about, there are far more on the Dodge. It has a bit more ground clearance, but still has vulnerable waste plumbing under it. The shorter wheelbase helps a bit there. But it has no cold weather water capability like the later ('02 & up) Express-based Chevy 190's. Some Dodges have driving/handling issues (BTDT); be sure to read the 'test drive' part of the FAQ's here. The Chevy Express RT's of that era drive fine, but sit pretty low and have a longer wheelbase. I've owned one of each. I much preferred the Chevy, but it had its limitations on rough roads. I did spend a fair amount of time of forest service gravel roads with no ill effects, tho'.
Sleeping three is very possible in either a Popular or Versatile, as long as the third person is not too large and is young & limber. The second-row seat makes into a bed, tho' not a very comfortable one. Some memory foam would improve that, I think.
Even a 190 has enough room for a family of three, if you're active and don't tend to 'couch potato' it during the day. The old 21' G-30 based 210 is fairly rare.
One issue may be boat launching. With the Onan under the floor behind the rear axle on all the 190's, it's vulnerable to dunking. I'd want either a hitch extension or a front hitch, either just for launching and retrieving. The 210 has the Onan above the floor.
HTH. I think you'll use the B a lot more than a large C. It can even be a daily drive, or a local festival or "go to the kid's ballgame" hangout.
Jim, "I hate it when you offer someone a sincere compliment on their mustache, and suddenly she's not your friend any more."
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')