San Jacinto Peak, the long way
Hiking San Jacinto Peak the long way is quite a challenge. There are several routes to the top, this particular one starts in Humber Park in Idyllwild. Another variation can come from the Palm Springs Tram (though it would be less than 10 miles round trip). To make it even more challenging, you can come from Humber Park also, but follow the PCT for a bit, which adds 3 miles to the one way total. Regardless, getting to the summit is a great accomplishment, and puts you to almost the highest point in Southern California at around 10800 feet.
To get started, take Devil's Slide to Saddle Junction. Once there, bear left following the signs to San Jacinto. The next signage you will see will be at Wellman's Divide, at that point you are almost there. Head left up the hill until you get to the hut at the top. There the trail ends and if you want to actually summit you need to scramble up the rocks another 300 feet or so. When you come down, don't lose your bearings. It is easy to do since there is no trail between the summit and the hut, so be careful and don't go wandering down the wrong way. Expect the entire hike to take 8 hours give or take some depending on your conditioning. Also, it can be hot, bring plenty of water, probably upwards of 4 liters per person to be safe.