This website and app allows you to create a route by entering locations, and coordinate how many days you will stay in each spot. The time to travel between each stop is automatically calculated. You can also see a summary of gas usage, miles traveled, and hours traveled.
This site is a lot like RVParky, but it’s $30 a year. You can look for fun and unique stops along your route, though, which is handy!
I use CoPilot, a free app on my iPhone. When I first downloaded it, I input my RV’s height and length, and I haven’t had any problems! You can download maps by region so you’ll always have directions, regardless of your cell service.