The City of San Antonio offers a free "E" shuttle in downtown. For TxDLA guests, it requires a very short (2/10 of a mile) walk to the pickup point in front of the convention center (right next door to the conference hotel at 200 E. Market Street). The shuttle stops at various points of interest in town and runs Tuesday through Saturday from 6:00 p.m. until midnight.
For the Wednesday night dinner at the Grand Promenade, take the shuttle to the LaSoya and Commerce Street (near McDonalds) for a short 240 ft walk to the Grand Promenade Entrance if you would like to shorten the total 3/10 mile walk.
Download the map at http://viainfo.net/BusService/Docs/EntRouteWeb.pdf.