We are almost 13 feet tall too. We have the Garmin dezl 760LMT as well. It's not fool proof. We usually do our research before going on our trip by using the Rand McNally Truckers Atlas that shows what highways are safe for Tractor Trailer's (Safe for a tractor trailer, Safe for an RV). Then we map our trip online using google maps, and finally we do the trip planner option within the Garmin using the roads Google Maps has made for us. This method hasn't failed us yet. We also just recently bought RV Trip Wizard so we now can also find campgrounds and fueling locations easily.