I went to GCR Tires & Service at 2815 N 32nd Avenue, Phoenix, AZ 85009, (602) 272-9308. They looked at my tires and said, "You don't need new tires at this time. Bring it back in another 5000 miles and we'll check again." I can't think of any reason they would turn down a sale of 6 new tires, mounted & balanced except that they're extremely honest.
It's about 100 miles from Prescott but it's an easy drive once you get on I-17. HTH
2010 WGO Vista 30W, 1993 Geo Tracker
Just a user with no RV or mechanical expertise