Go to
RV Parky, Sign Up (it's free) and start a new trip. Put in a starting location, then put in your ending location. It will then give you a map in the right pane showing its proposed route. On the left pane you will see your two stops. You will notice your last stop has a "Find a Place to Stay" button. Clicking on that will show you every place you can park an RV near that location. I normally filter that list at the top to remove all Stores, Gas Stations, and Other so that I only see campgrounds and RV Parks. You can then find your desired park by reading reviews, etc of the different parks.
So that would have the ending location set! Then you figure how far you want to drive and put in the location of your first stop by clicking the Plus symbol between your starting and ending location. And just keep doing this until until you have your trip configured. You input the city and it will list the campgrounds in that area for you to select, all the time showing your progress in the map pane. You will notice that it allows you to put in howmany days you want to stop at each location and will keep your dates current and also tell you the distance between stops.
We have used this for our last three summer trips and love its simplicity. We also have the
RV Park Reviews site in another tab so we can also use their reviews for parks we are looking at.