Favorite thing: To the east of the mission, there's a small hill only about 100 yards away. You can walk around the hill or climb to the top (only a few minutes hike). At the top there's a statue of some saint. From the top you can survey the floorplan of the church and the surrounding area.
San Xavier Mission is a typical Spanish Mission of the Southwest. Take I-19 south and exit at San Xavier. It is on an indian reservation about 15 mins. south of Tucson.
Fondest memory: San Xavier is a typical Spanish Mission of the southwest. There are elaborate paintings and a shrine to San Xavier inside. There is a small museum, a hill you can climb to the top of to get a nice view, and usually there are some native americans selling fry bread outside. Definitely try it, it's yummy.