If you're going from Florence to Tucson via Hwy 79 I must warn you it has no shoulder and the speed limit is 65mph but people do more like 80mph. This is a very dangerous road with tons of traffic. But if you do decide to go Hwy79 then you can take Park Link Road at around Mile Marker 101, that is 18miles long, and connects to I-10. You'll end up just a mile or two north of Red Rock and another ten miles down the frontage road you end up in Marana. I live off of the Marana exit about two miles. Cold beer is in the fridge!
Tucson pretty much begins in Marana. From Marana you could ride the back roads that goes through Saguaro National Park and end up coming out either South side of Tucson or all the way in Ajo. It's very pretty taking the back roads (Sandario Rd.) It also goes to Gates Pass or Old Tucson.