Major Tom have you ever visited the sites airforums.com ( for Airstream owners, Airstream makes the Interstate, a class B, and has a section on those type units)?
Or.. forestriverforums.com..?..a site for Forest River owners...Forest River is owned by Thor Industries which make the majority of US RV's ( including Airstream trailers)....
I used to dream too of buying a motorhome or trailer+truck and doing the RV thing....until I spent years on these sites seeing the unbelieveable problems people have with NEW units, much less used ones.
Sort of took the shine off the idea of owning one for me.....
One thing most of the forum members complain long and loudly about is servicing the units after purchase.....poor service networks, and the servicers don't have to touch yours unless you bought it there. Not like car dealerships which will work on your car no matter where you purchased it. Dealer networks from what I've read, for the most part stink. If you're not mechanically inclined, that could be a problem.....
The other thing is that RV'ing has become so popular in the last few years, they are banging them out so fast the quality control appears to be non-existent. This is even true on 100,000 dollar Airstreams.
I read those forums for hours during the long cold winter months and decided it's probably not for me.....