If it helps most of the good & local restaurants are downtown off of Congress, within ten miles. If you find a parking garage on Congress St; or circle left on 6th to Pennington St., you can park and walk around downtown. Cafe Poca Cosa is adjacent a parking garage, so you could have brunch or lunch there. I recommend a stroll down to Congress Hotel. You may have to pay a cover fee if there is a show on, but if you pick up an issue of Tucson Weekly, you'll find available around every street corner downtown, you'll find lists of shows, bars, and events going on. Not to mention a good read.
Maynard's Market & Kitchen is another great place, if you don't mind casual fine dining. It was a place I applied to be a Sous Chef, before ending up in South Carolina. Woody's Restaurant and Gay bar, will probably opening up downtown on Congress, so you may see that if you decide to walk around. IBT's is a walk through the underpass, and less than mile away from Club Congress. You'll find one of my favorite places in the World, 4th Avenue. No shortage of bars, cafes, restaurants, college students; punks, hipsters, and gays there! Wander about, find something that appeals to you, and explore. It's a gem!
My final recommendation will probably have to be in another direction altogether. Casino Del Sol! There is a Japanese Asian/Sushi/Bar called "AN Del Sol". I recommend it! Have a dragon roll, and saketini's! The bartenders are the best, and great when they're not pouring out drinks! There'll probably be a game on one of the several widescreen tv's. Hope you like sports! Take your sister with you, don't gamble your savings away, but here's a tip. The slot machines right outside the entry way to the restaurant aren't cash cows, but pay out more often than most.
If you want to see the city skyline and get some exercise, climb Tumamoc Hill, off of St. Mary's, just behind St. Mary's Hospital! It's a progressively steeper inclination to the top, but a rewarding panoramic view, and great way to start your day, before going to enjoy yourself about town. Buy some bananas, protein bar, coconut water, or gatorade, at the Food City or Safeway or Circle K, down the road before your hike! You're gonna need it for your dry air hike.
Hope you have fun, and take pictures! You'll be seeing Tucson through my eyes. Cheers!