I have used E. Dan Klepper's book 100 Classic Hikes in Texas for exploring Big Bend National Park. There is a section in the book dedicated to the most popular trails in the park. When dad and I went a few years back, we relied on this book to help us decide which trails to hike.
This is the Recreation.gov direct link to Chisos Basin Campground. This is how you book your reservations if you intend to stay in the campground. From this campground you can hike several trails, plus it's close to the main restaurant and general store. The reservation system allows you to chose from available dates. Usually booked out several months in advance for the good weather days.
Dad and I planned and took a trip to Big Bend and we recorded a podcast series about it. This link is to the Epic Field Notes podcast category, which you can also find on Sticher and iTunes. We don't do this podcast any more, but the episodes about Big Bend begin with Episode 31. We had a great time doing this podcast.
This Chisos Mountain Trails Map 2017 is full color. I ordered five of them, and paid only 1.39 each plus 3.50 for shipping. It unfolds to 22" x 17". Dad and I used this official map when hiking from the campground. It also shows the primitive camping sites for those who wish to backpack and camp up in the mountain.
You must reserve a primitive site in person to remote camp in Big Bend National Park. Here's a link about remote camping permits for the primitive sites. When dad and I went to the visitors center to reserve a site, we choose from a handful of remaining sites. Get there early because the sites are booked on first come basis up to 24 hours in advance. Campsites around the South Rim go fast because the rim is a popular destination for hikers. Check out this awesome 46 page guide on backcountry camping in the Chisos Mountains.
“Star-gazing with Binoculars and the Naked Eye” - I highly recommend this educational ranger program if available. You drive out into the dark desert and meet with others in a dark parking area. At first you may feel uncertain if you get to the meeting spot first, but when the ranger and other cars arrive you'll sit or stand out in the open while the ranger uses a laser pointer to present the stars and constellations that can be seen with the naked eye. Bring binoculars!! I had never used binoculars before to view the night sky, but the experience was one of my most memorable parts of my visit. Ranger-Led Programs are listed week by week, so this tour may or may not be available when you go.
Dangerous Wildlife: Scorpions, Snakes, Cougars, Bears. Yes, they are there, but we never saw any. I spent quite a bit of time researching snakes and such prior to visiting. Now that I've been there, I don't worry. The trails are well-traveled and the campsites well-used. I'd say the chance of a snake or scorpion crawling into your boots is slim to none. As for cougars, the only time I began looking over my shoulder was while hiking up Boot Canyon Trail. That trail had few other hikers at the time, plus my dad had fallen behind. I found myself alone in what looked to be perfect cougar ambush territory. At one point, I hiked on a section of trail carved along a steep hillside between the stream and what I fantasized were cougars watching me from above. I couldn't think of a better place to be ambushed. Stick close to your hiking partner and keep an eye on the higher ground. Hiking alone can be freaky.