We love Tanque Verde Guest Ranch. Since we usually stay at my mother's home in Tucson, we have never stayed at the ranch. However, we have been there many times during the past 20 years for dinners and lunch.
The ranch is beautiful and has wonderful mountain/desert views. The food is great and you will likely find guests from many countries.
Tucson has many things to do and is easy to get around. The city thoroughly embraces the University of Arizona and you will find people of all ages (even snowbirds) take advantage of the arts/sports/museums/planetarium on campus.
The Arizona Desert Museum is on the opposite side of the city, but it is a beautiful drive through Gates Pass where you will see huge saguaro cacti. The museum is an annual must do for my 9 year old daughter. She loves the desert, the animals, and the very friendly docents.
You will find great places to eat in Tucson and a cheap must have is an Eegee. It is a frozen slush made from fresh fruit. GREAT way to quench the thirst in July before the monsoons!
Another great place is La Fuente. This well established restaurant is family owned and attracts both locals and tourists. The chimichangas, cheese crisp, and made-at-your-table guacamole are fabulous.