If she was in NV while pinging in AZ, she would also have been pinging in NV. That's the issue.
However, I did have a thought that JA made those calls in AZ because she just couldn't help herself and then for whatever reason--maybe it was Val who suggested this--backtracked to avoid Hoover Dam, and ended up on 95.
I don't think there was enough time, but that's based on the (unsubstantiated) premise she travelled 60 to 17 to 40. It took me 4 hours to get from Mesa to Kingman, midday on a Saturday, not during week day rush hour congestion.
Fastest possible case, and I think unrealistically fast: Let's say she left Mesa at 6, arrived Kingman at 10, went halfway to the dam and turned back, which would make it around 11. (71 miles between Kingman and the dam).
It took me 45 minutes to cut across to laughlin NV on 68, and if she went on 95 then, she was lost too, and driving in the wrong direction, towards Needles. (and the ping would be way further south than 27 south of Hoover dam NV; a Kingman tower would be closer).
BTW, because it's relevant to gauging time, I confess to routinely driving 5-6 miles over the speed limit when I'm driving long distances, and on deserted stretches, up to 10 miles over, which on some of those roads means 80-85 miles an hour.