San Antonio Living History Association (SALHA) is local and does the Alamo once a month (next one is Sept. 7th). Come out to the Bullethole on Grosenbacher Rd. 6pm-8pm today and some of us will be shooting.
The Refugio Militia is still around and has a pretty good website. I think the Texas Army is around too, and the Alabama Red Rovers. I think the Crossroads of Texas (??) do Goliad.
If I sound vague on these its because in my first year I've been to most of the Texas Rev War events and signed up with various folks, even paid dues, never heard anything back. Not that I'm complaining, doesn't trouble me at all to give the nominal annual membership fees to those sort of groups, just didn't seem to make much difference in my status is all. I believe I could have equally done all the events as an independent.
Most every event I've been to has been on a walk-on or pre-register as an individual basis: Show up correctly kitted out, sign the waver, pass the safety inspection and you're good to go.
First Saturday of every month at the Alamo for SALHA (monthly Sunday afternoon meeting dates on their website), the first scheduled Texas Rev War event IIRC being at Gonzales in October (I'd have to google it for the date).
Birdwatcher