Texas actually owns plenty of "public land", which is seperate from private property, but that doesn't necessarily preclude general public access at any time to said properties, nor unrestricted use of said properties (think state parks, national parks, wildlife refuges, etc.).
To my knowledge, you are not allowed to collect any piece of your surroundings from any of the above examples without breaking the law though.
so the long and short, you're still screwed unless you know somebody with some privately owned property.