I'm baaaacckk! Hey, Rich & Rob!
Not quite caught up to reality; my soul is still at a rest-stop somewhere around Biloxi, I think...So now I'm email@example.com
A good "window" looks like March 26th through April. My calendar doesn't indicate when the full moon is, but that's the best time for calling. They hunt more during daylight, then. (Easter ain't a factor for me.)
I can't get a game warden down in my country for mule deer season, much less varmints...
Terlingua airstrip, about four miles from my house, is a very smooth, 3,000 foot, caliche strip. Lajitas, a few miles west, has a paved strip (no lights) some 4,400 feet long.
Whatever rifle is the most "married" to you is probably best; .243 is plenty big, and .308 shoots flat enough...Otherwise, bring whatever toys turn you on.
Terlingua is some 650 miles SW of Dallas, at the west edge of Big Bend National Park. By March, we get an occasional low below 40 degrees, but rarely a high above 85 or so. Night-hunting hours are cool-to-chilly. It's usually dry, but no absolute guarantees.
Query as you see fit. Nuff fer now, Art