RV Trip Wizard it the best planning software out there I moved over from Good Sam about a year ago, its $39 a year and well worth it
I have used to plan a 5 and a 6 month trip covering about 12,000 mile
This is from their website
Rand McNally Dock
The Rand McNally Dock works with the both the Good Sam and Rand McNally RV GPS units.
The Dock sofware is available at http://www.randmcnally.com/support/s/dock-software
After downloading the trip GPS information to your computer, run the Dock software to bring the information into the Rand McNally GPS.