I think you will get more appropriate response to this in the Winnebago Owners forum, so I am moving your query there.
In general, though, the warranty is from Winnebago and good at any dealer. Whether a dealer elsewhere will give you second-class priority depends on the particular dealer. Some go out of their way to help travelers and some seem to be uninterested in servicing anybody at all. It's a grab bag.
Former owner of 2004 American Tradition
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC