Contact GD and see if they'll authorize you to go to ANY dealer or use a mobile tech (you'd have to pay the travel cost for that, though).
Grand design told me that I can go to any dealer, or call a mobile tech, but as you state I would be on the hook for their travel cost. I am not willing to pay anything for them to look at my trailer and pass it. That includes me driving to the closest dealer (one hour away). I called our dealer and when we go that direction in September, I will set up an appointment for the trip home. We will drive more or less past them going home anyway.