It's not a day trip for me, but rather a weekend or long weekend excursion to Austin, but I've been to the county park many, many times, over many, many years. I'd rather drop the bibs at a resort in Jamaica or at a resort in Florida, but when a weekend is all I have, it will do. There are unofficial "sides" where the gay and straight tend to congregate. I just have to watch when I leave because some folks are wannabe stalkers and seem to want to follow me.
Oh, and if you visit, bring a folding chair/recliner. Also gets you above the insects. This is not a manicured tourist spot. The rocky shoreline is not a sandy beach, and good sandals, not flip flops, will save your feet. I use a pair of Chaco's, vibram soles and the thin webbing is great, no real water retention, and they are fine to swim in and the soles help on the rocks getting in and out of the water.
