N.B.
I think the place by Rancho Solano on Gilbert Rd. that someone below referred to is Called Shenandoah Mill or something like that :) I had a friend get married there once and it was a beautiful wedding. No idea on their prices, service, etc. For my friends wedding, the ceremony was outside with the reception inside.
Also, I'd highly recommend a place called Inside the Bungalow, previously known as Coffee Talk. It is so many different things rolled into one...it's in downtown Mesa off of Robson. It's super cute and pretty reasonably priced. The building itself is a coffee shop/cafe/yoga studio, but they commonly hold events, including weddings, outside on their grounds. It's a very cute, quaint little place and I love it. It does depend on her taste though, as it's very unique and old fashioned....hard to explain :) Hope this helps.