It seems to me that as long as the dealer has a contract with a manufacturer ,they should be obligated to repair a problem, no matter where the unit was purchased.
I worked for an 2 RV dealers in Ocala, Fl. and we did warranty work for anything we sold and a lot of what we did not sell, we still received payment from the manufacturer.
2002 Rockwood Freedom 2318G
2004 Ford F 150 5.4 liter
3 Chihuahuas Sammy, Delilah,Gypsy