I believe I'm the nearest person on attackpoint to you (in Houston), but I know there are orienteers in San Antonio and San Marcos, if you want me to put you in touch with them. There's an orienteering event at Bastrop (near Austin) organised by Houston Orienteering Club on November 6-7 (see
http://hoc.us.orienteering.org/ for details when available).
Some of the state parks to the West of San Antonio my be good for running - for example Hill Country State Natural Area near Bandera. Check out
http://www.hillcountrytrailrunners.com/ for more ideas (atlhough they're based in Austin, they may be your best source of information).
John