I bought my Northwood Fox Mountain 300 miles from my house. In fact there are no Northwood dealers closer than 50-75 miles away. Northwood has replied to an email I sent regarding warranty work when out of state/town. They will allow me to take it to any competent service shop.
I would call the manf and ask what their policy is. We purposely didn't buy from one of the dealers that's 75 miles away. We felt it was worth the 300 mile drive. While we never dealt with the closer dealer, we had just not heard anything positive.
We did buy our last TT local and although we had minor warranty items it was nice having a local dealer. I guess it all boils down to the fact that most warranties are 1-2 yrs and most people keep them longer than that. So in reality unless you have a ton warranty work needing to be done it's not that big of a deal. Your local dealer isn't going to give anything special when you're out of warranty. I would be more concerned about buying a better quality unit than having to worry about warranty work.