Anyone know of any mountain biking trails in the Grand Canyon area, South rim? My wife and I are taking a few days to road trip up to the canyon and would like to do some mountain biking. I have heard good things about Flagstaff and Sedona, but was hoping there might be a trail or two closer to the park as the trip is not just for biking. If not, any particular trails you would recommend in the aforementioned locations for beginner riders? Thanks.