I didn't see this post, I am glad you brought it forward. Yes, very strange. You can see the racetrack in your map. Very close together.
All this time, I had imagined SK further south in Vegas....yet, he pings on one of the northernmost AT&T towers ... and the call ends up on "Rocket" tower (which I've yet to find). That indicates he's driving. Steven could have made it back to St George, as quickly as GW, then.
Has anyone else located any of the other towers?