Gaia is fantastic. Gaia is a proprietary app but not designed to go into a GPS system. It can be used on any iOs or android device (tablet, smartphone) It has a great route-building system, creating way points is easy and route recording is a breeze. It works great offline, but you do have the...
In premise, you've got it. As long as you disconnect the driveshaft you're golden. I would look into the Renco disconnect. In practicality, fully disconnecting/connecting the driveshaft every time you want to drive it sounds like the biggest pain in the ass and would get old FAST (to me).