Best I have found is Goodsam trip planning on line - used it for a couple of years now
Good Sam's Trip Planner features tools and information designed to help you have the best road trip - every time. When planning RV or car trips, you can make use of:
• Point-to-point trip planning
• Research and add Good Sam Parks to your route
• Search thousands of Points of Interest and add to your route
• Calculate fuel costs and travel time
• Options include avoiding highways and/or tolls
• Use RV travel filters to see low clearance and tunnel warnings
• Download trips to your Good Sam GPS
http://www.goodsamclub.com/travel/freetriprouting/