For your situation, I would think that a local dealer with a good reputation would definitely add value. How much value would be the unidentifiable part since a lot of that is about personal preference and the unknown amount of service required.
On the equipment side of purchase: I think a dual paned window is a good thing to have. How many standard add-ons is the seller including (hitch, propane, batteries, etc)? Also, if it was me, I'd be looking underneath any selections--how is the frame built? Is the fit and finish of the underside good or just adequate? Are there water lines and propane lines run underneath--how close are they to wheel wells? There's a lot to be learned by looking at the things most don't, if they took the care to layout and install well in those areas, trust could be assumed for the top side.
Good luck with your choices!
