I did this trip in December. The Chisos Basin car camping sites are actually pretty cool, we did the first night there.
We did find water in Fresno Creek, but it was pretty greenish and undesirable. I wouldn't count on it now. I carried 6 liters until the water cache, this was about right.
The trailhead is to the left of the Chisos Basin store / visitors center. If you are in decent shape this should not be a difficult hike.
When we went they had recent bear activity near the JC1 campsite. We did not hang our food and were fine.
The first camping spot you come to in Juniper Canyon is either non existent or in disrepair. We didn't find it suitable. Keep going down the back side of the mountain and on the way down Juniper Canyon you will find a good camping spot off the right side of the trail cut out of the thicket. Once you finish descending the canyon and it gets flat there are a few other spots to camp.
From Juniper Canyon Road onward the cairns are pretty good. You do go through a number of washes and eventually get into the riverbed but again there are huge cairns, just keep your eyes peeled.
I assume you are going to cache your water off Ross Maxwell Scenic Drive at Homer Wilson Ranch. Make sure you put your water inside the bear box.
Let me know if you have any other specific questions and have a good hike.