Just spent the weekend wandering around five missions in the San Antonio area. The Alamo is maintained by the Daughters of the Republic while the other four are maintained by the National Park Service and the Catholic Church with all still in operation.
The Alamo is a nice place to visit but I preferred the four other missions because they were much less crowded. The National Park Service calls the trail a 'hike and bike' trail, but you're much better off driving the route.
Not a bad way to spend a weekend...
Here are some photos:
http://travel.webshots.com/album/559892117LAHtur