Fort Sam Houston wasn't that impressive when I was there, but then, I was briefly living on it. The officers' housing was lovely to drive by. You've already mentioned the Riverwalk -- go to 'Dick's Last Resort' if it's still there. The Alamo Cafe, near the airport, had great food. I'd be in SA every year until I retired from the AF, and made a point of going there for Chili Rellenos. The challenge was to not pig out on their tortilla chips, guacamole and salsa. We had folks coming home with gallon jugs of their salsa!