On our trip out west last year I used a combination of Rand-McNally trip maker and RVParky. With RVParky you can put in your destination and use the "Find a Place to stay" button and review all the places in the area that you can stay overnight. Once all done I just duplicated everything on the RM trip planner. It takes a little more work then just the GS but I felt it worked just as well.
For those of you that are IT and GPS experts, there is a way to download the RVParky plan intao the RM gps. I dnt have the needed skills to do that but from what I have readit seems to work just as well. I just looked at the RVParky web site and it appears that possibly they have made changes to be compatible with RM but I would look at it to be sure.