Most of the traffic is on the SD County RCS system. You can put in the East loop and listen for Imperial Sheriffs office. I have heard that is not the best way though because there are a lot of sites in Imp Co. that are not part of the east loop. These sites do not simulcast so you have to be listening to the site that the mobiles are associated with. The Black Mtn site would probably be better for O'wells than Superstition.
I stay over in the Plaster City or Superstition areas so I don't know what you'll hear in O'wells. I am going to be out there this week as well for an offroad race. The pits and start/finish is at Plaster City West.
Good luck, have fun, and be safe.
P.S. Don't forget the BLM freqs.
166.7500 BLMLE
167.1750 BLMSMP
168.1500 BLMOPS
169.7000 BLMNSM