Be sure to check the
Lost Maples Fall Folige Report... there won't be any appreciable color change for a little while yet. We need the temperatures in the Hill Country to get a bit lower.
In answer to your question, we are a little sparse on the backpacking opportunities here in South & Central Texas, I'm sad to say. However, if you don't mind the trek out to Bandera, Texas, I'd say you cannot go wrong with
Hill Country State Natural Area. I know it seems like it's my answer to every, "Where should I consider going?" question but it keeps fitting all the criteria -- lots of trails (36 miles; some is hiker/backpacker only; the rest is mixed use, equestrian/bicycle/hiking, but plenty of room for everyone), solitude, minimal light pollution, great scenic views, plenty of wildlife (snakes, songbirds,
eastern cottontail,
armadillo,
raccoon, wild turkey, etc.)
Here are some of the non-federal land
statewide backpacking options, compiled by the Texas Parks & Wildlife Department. I haven't visited most of those, so I can't compare them to Big Bend National Park (where I spent a week camping & hiking and wanted to stay there forever...) or Hill Country SNA.
-- aside --
I am eagerly awaiting the public opening of
Government Canyon SNA -- 8,201 acres of beauty in far NW San Antonio. The trail system will be the most extensive in the region, boasting 41 miles of trails! Read about a 1999 mountain biking club's experiences riding the single-track trails they'd recently helped create --
Government Canyon Story.
According to a July Austin American-Statesman article, the U.S. Fish & Wildlife Service has hopes of purchasing another 855 acres of land adjoining the SNA to serve as further buffer and conservation area.