The Falcon International Reservoir was created in the 1950s by damming the Rio Grand south of Laredo, Texas. I'm camped three miles from the border at Falcon County Park. Free camping, water, toilets, showers, some electricity, tables, fire pits, etc. And trees. Haven't had any of those lately.
online sources like FreeCampsites.net or Campendium.com.
Right now the grass is mostly brown and some of the aforementioned trees are bare. It's probably a lot nicer in spring, which is technically just a month away.
My GPS unit got me here from Port Mansfield without using any interstates and scarcely any divided highways. But that's okay, because Texas, knowing it's large and spread out, has high speed limits even on two lane roads. And traffic was light.
It was sunny and warm with perfectly acceptable humidity. Not desert-low, but comfortable. Meanwhile, reports from friends say it's windy and wet in the Yuma area. No rush to get back there.