I hiked the Ernst TInaja trail as part of a 4 day backpacking expedition through the backcountry trails of Big Bend National Park. The hike occurred on the 4th day on my way back in. You can read my log of that extended hike here.
The Ernst Tinaja Trail is a very scenic trail that takes you through a magnificent canyon. On display are impressive layers of sedimentary rock, sculpted boulders, and pools of water. The trail continues on for quite aways, but requires some rock climbing and balancing skills to get to the deeper recesses. Eventually, you exit the canyon on the other end and come out onto a desert plateau.
I highly recommend this trail. It exceeded my expectations. My only regret is hiking there early in the morning before the light was ideal for photography...
Rock folding is wonderful! Allow an hour for the slow going access road. Lots of climbing to get to the end of the canyon.
Getting to the main tinanjas involves various stages of readiness. To use the old ore rd, a high clearance vehicle is best. (you don't need 4-wheel drive)
Once you get to the parking area, you have a nice easy walk to the tinajas, with only slight elevation changes.
It becomes a level 4 or 5 difficulty if you decide you want to cross the main the tinaja. I have gone THROUGH the tinaja (when super shallow) and climbed the wall of rocks. I have went up and over on the left side and up and over on the right side. Either will take guts and balance. Be super careful. Coming back stay on the right side (as you are facing OUT towards parking lot) and go about halfway, then slide down the smooth rocks on your bottom. Have someone there to catch you.
It's a great hike and spectacular colors in the rocks to see.