I agree on Cade's Cove. I would suggest not taking the class C on the Cade's Cove loop itself, though; while the road can accommondate RVs in theory, there are (or were when I went) a fair few low branches and in places where other people stop and pull "off" the road the gaps are sometimes very very slender indeed.
Dollywood is not just for kids; it's a lovely amusement park in all regards. If you're not much into that sort of thing, of course it's reasonable to skip it; but there are plenty of "grown up" rides and shows and craftspersons and such.
