Great workout! Bring water and more if it's hot. I had 2 liters. There were wildflowers, loose gravel, sand, boulders, little itty bitty stream and markers to help guide you as you get closer to the top. You should be in decent shape and take your time. We did it in about 51/2 hours.
This is a very strenuous hike, but worth it if you're in good shape and want a challenge. I've done it three times and have finished in just over 4 hours. BEWARE, however, on my most recent trip there my car was parked alongside Wildcat Canyon Road and when I got back at the end of our hike it had been broken into (window shattered). I had nothing of value in the car (they did take my registration card and appeared to be looking for a hidden car key.) No other cars around mine appeared to have been broken into so beware that this is a risk and definitely leave nothing of value!
Hardest trail in SD so far. Took 6 hours out and back. Encountered 3 steep mountain to reach El Capitan reserve. I consumed 4 big bottles of water. Spectacular views on the top. Finally saw a rattlesnake slithering about on my way back. This trail needs s lot of endurance, leg strength and balance! I'm glad I did it for my bucket list.