Class C. Parking in San Antonio for Alamo and Riverwalk?

Agree that the Alamo is in the heart of San Antonio, about 500 ft. off the sidewalk along a busy street. The parking lot was across the street but it was full. No place for a 'C' pulling a toad.
So I saw it when I drove by. It looked a lot smaller than when Davy Crockett was standing on the wall in the Disney Classic. Next time thru, I'll overnight at an RV park, and see if I can hook up with a tour.