Looks like a good option. We are currently using Let's Go Aero box. It holds 2 road bikes with the front wheels removed. It also slides out about 18" to allow access to the rear doors. In order to use it with mountain bikes, you would also need to remove the handle bars. It's pretty stable off road also. It's pretty heavy though to get into the higher hitch racks on the EarthCruiser bumpers. I am thinking about using something like this Slide Out with the Thule ThruRide fork mounts. I would then get a custom canvas cover made for dust and rain protection.