I use a Rand McNally RVND 7730 as well. Really like the unit with the settings to configure RV length, width & height so you don't catch that low bridge. I also had to disable the annoying "Speed Warning". Bought mine on EBay from an individual that evidently bought an in dash unit. Very pleased with the performance but I also check it against Google Maps because all GPS's are not always showing the best route.
Jim K - Avenue, Maryland
2016 Thor Hurricane 35C
2015 Ford F-150 King Ranch
2013 Chrysler 300 "S", 1936 Chrysler C-8
2012 Jeep Liberty Limited Edition