reviews of the extended service plan?

After a long search for just the right vehicle, I'm in the process of buying a class A that will be the first motorhome in my family in around 20 years. It's a used rental unit, so mileage is high (90K) but it has been well maintained and I have the service record for its complete life as a rental. It comes with a 12/12 powertrain warranty from the dealer, and 30 days on major appliances.

Does Good Same sell extended warranty coverage for higher-mileage vehicles like this? If so, what is the max mileage cap?

Thanks!