We had all 6 tires replaced a few months ago, after a blowout to an inside rear tire. Our tires were 7 years old at the time. They looked to be in great shape with very minor cracking on the sidewall. With 29k miles on them, they looked to have plenty of tread left.
We replaced them with Michelin LTX M/S2 tires (stock were the LTX M/S). We have a trusted repair shop that we took the motorhome to. I also had them install TireMan's solid valve stems at the same time.
We have AAA and they have been very good to us, but they will not replace a tire if we don't have a spare. Just to put our spare on, the mobile tire repair guy charged AAA $250. He would have probably charged more than double to put a tire on the wheel and then mount it.
-Michael