Here's a couple of ideas:
Palacios RV is big on interior and exterior work in Phoenix. They started as an auto upholstery shop years ago and branched into major RV work.
Look up AZ Expert. He is a talented RV tech and has a popular YouTube channel. He has a shop but doesn't promote it by name, you have to email him.
You can email him: [email protected]
Also, there is a National Indoor RV Center in Phoenix. They have a great reputation for repairs. https://www.nirvc.com/
I don't think any of them are close to Fountain Hills.