i have the garmin 465T. gives truck routes, bridge clearances, and truck stops. although it is made for the trucking industry, it works well with the travel trailer. Cobra also makes one.
u can switch it to car mode if u aren't towing.
i understand that there is one made specifically for the RV (by Magellen?). there are a few post abt it but i have no experience with it.
i find, when i'm towing, i want the truck routes. would prefer one made specifically for the rv industry. what comes to mind is that the rv is allowed on the Natchez trace but the garmin, in truck mode, simply tells u to get off. i have to put it on car mode to use the trace. when i do, i loose the overpass and curve warnings.