One alternative to San Antonio could be the Stagecoach Inn in Salado. Many car clubs use that venue for weekend "meets" during the spring/fall times of the year, with a casual car show in the parking lot, then head into the meeting room or restaurant for the evening meal/program. The Houston area chapter (Lone Star Chapter) of the Buick Club of America will be there (with other BCA members in TX) on April 16-18 and the Lincoln Continental Club people will also be there that same weekend. Pretty nice place to kick back too. If you check the LCOC website, they're having one of their national meets in SA in the fall also. Several possibilities.
If anyone's interested, Cowtown Mopars Performance Team will be having their annual show at Huffines Chrysler, Jeep, Dodge in Lewisville, TX on April 10th. I suspect the San Antonio Mopar club will be having some event in the spring/summer also.