Base Camp from Gamin is free and runs on Windows or Mac using the maps from your Garmin GPS. You can plan a trip and upload it to your Garmin.
The downside here is you need to have a Garmin GPS or you need to buy the maps from Garmin that you can load for Base Camp. The other nice thing is you can find custom and user provided maps that can be loaded and used as well. Things like off-road trails, hiking maps, topo maps, etc. Not all that usable for an RV, but great for the Jeep or for hiking.
It does seem a bit "clunky" to me though, at least on a Mac. Haven't tried it on a PC. It works though and is compatible with my portable Garmin.