I don't trust my Garmin (the one specifically for RV's) unless I am on a four (or more) lane highway. It is never reliable on backroads. I go to Taos, NM at least twice a year. There are a couple routes I take depending on if I am towing or not. One route would be a disaster with our 37 foot trailer because there is one turn that could not be made at all and it would be impossible to back up. The other route is a simple direct and shorter route but the scenery is not quite as nice. Guess which route my Garmin wants me to take? Never really trust any GPS.