Survey results from 1999 named Hidden Valley as the most requested trail. Honestly, I wasn't looking forward to the hike having mountain biked the area several years ago. Now after the hike I have a different view of the area.
Yes I am likely the lone idiot to have mountain biked South Mountain on the hottest day ever recorded in Phoenix. It was 122 degrees. I downed two water backpack reservoirs and two water bottles on the frame. At the end of the day I was eight pounds lighter.
Today I put those worries behind me. A cool 82 degree February afternoon was perfect South Mountain strolling weather! Memories left me believing this was a hill covered with mammoth cow patty shaped rocks. Today I was a bit more impressed with the surrounding area. A rare clear day presented itself. I put the mountain range skills into effect. Pointing out the Sups, Four Peaks, Pine Mtn, Mt Oro, the continuing Mazatzals, McDowell, Bradshaw, Whitetank and Estrella Mountains along with Camelback and Squaw Peak Mountain Preserves too. This was necessary as days before I felt a tad under par. A beautiful young lady asked what are those mountains as I stood upon Wasson's Peak. Not knowing the Tucson area I said Catalina's "I think"?!
Hike From the trailhead head on out. You will be following a section of the National Trail out to the Hidden Valley Lasso Loop. Immediately the trail skirts the mountain then soon goes to solid ground for the remainder of the hike. Be on the lookout for mountain bikers even though you have the right-of-way. This section of the National Trail is very flat for the most part. Mountain bikers love to open it up having battled countless steps earlier in their ride. The trail is easy to follow and fairly wide.
Turn right upon reaching the signed turnoff for Hidden Valley. Fatman Pass is encountered immediately, also called "Wonder Rift" on topo maps. This is a unique section where boulders leave a narrow gap you can try and squeeze through. Personally I never have given it a go, I just go over and look down into the narrow. Heading on the trail follows the wash in most places. You will be walking in three to four inch course pebble sand. Window Rock comes into play soon. Here again I go over. I do recommend the butt slide on the other side. At this point you really are in a hidden valley. It's pretty cool knowing you are in a valley above the Valley! Pass through this small valley. Just when you begin to wonder "did I loose the trail" keep following the wash. Bending to the right and back the wash will take you to the famous South Mountain Tunnel! This was pretty cool also. Staying to the left a six foot man can walk right though.
The National Trail is encountered soon after the Tunnel. Take a left and another left at the intersection with the Mormon Trail. It's easy hiking with little elevation gain back to your car at Buena Vista Lookout.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.