I am a big fan of Mexico! Glad your wife found something. A caution on renting a car in Mexico though...
The rental rates are very cheap, but the insurance will kill the budget. The minimum insurance during our recent Monarch Butterfly/Mayan Rivera driving tour onyl covered %20 of the vehicle cost, and not "incidental" damages (i.e. windsheilds) for $28/day. It took $45/day for total coverage. Full coverage is particularly important in Mexico because the authorities are permitted to lock you up if they think you can't or won't pay. And you will stay there until the issue is resolved to the satisfication of all involved parties. We got the full coverage, and were glad for it. The car was hit (minor damage) while it was parked in front of a hotel in Patzcuaro. The offending driver just left as if nothing had ever happened.