I was using Microsoft Streets & Trips for planning routes. MS dropped the program but I still used it until about 6 months ago when I got errors and it would not boot up. Since then I use Google Map to plan my routes. Not as convenient to my mind but it does work well. Once I plan the trip, I set up the trip on my gps. At times I do have to add extra stops on my gps to make the route fit what I planned on Google.
If you are a Good Sam member, they have an online trip planning site that works pretty well.
I haven't found any Android app that suits me for trip planning.
Pete - Full Timing
2000 Country Coach Magna 40' Indulgence, CAT C10, #5892
2019 Ford Ranger XLT