I would monitor the temps in the area that you're considering. Remember it's the warmth that gives critters their mobility. Pesky stinging, biting insects might not have had time to hatch yet but be concerned about snakes if the temps are consistently above 75 to 80 degrees. And feral hogs are a problem all over the state.
Hikers on the Lone Star Trail are already reporting sightings of snakes on the trail.
I don't know if I'd chance it without at least a lightweight tarp.