Perhaps Pinal County should be named "Penal County" because the major employers here are State & Federal prisons. And the list of things to do in Pinal County, Arizona is short. Nevertheless, all are worthwhile day trips from Tucson.
Florence, the county seat, has a lot to offer history buffs, including a small, but excellent museum & a pleasant walking tour of restored historic buildings.
Not far from Florence are two other worthy sites: (1) Casa Grande Ruins National Monument and (2) Picacho Peak State Park where every Spring they re-enact the Western-Most Battle of the American Civil War.
Just North of Florence is a fine Troon golf course.