Steve, I have many tools in my tool box for trips. I always start with trip wizard. I find it is worth the money and gives me great information for mileage, campgrounds, and routes during the planning stage. It does not have everything but their routing has improved. Once the trip is basically planned,I use google, and various books and apps. Google doesn't do low clearance and route preferences are for automobiles. I find it is a must to have my truckers road atlas book for low clearances, Next Exit for gas and food on interstates, RVPark reviews for CG information and gas buddy for diesel fuel.
Hope that helps