Good sport crags near Flagstaff are easy: The Pit, Jacks Canyon, Hobo Jungle. All have camping you can access. You can try Winslow Wall too but it may be a bit difficult to access in the motor home. You could just park near the McHood Reservoir and take a boat upstream for the DWS.
A big problem with camping in the forest around Flagstaff is fire danger and the closing of the forest to camping. Stays that way until the rains come in July or August.