Two Bar Ridge Trail
This is a remote trail that sees little traffic. It's 17 miles round trip and took about 14 hours of traveling time with a backpack and water for two days. The hiking is slow due to dodging Prickly Pear growing into the trail. Several times it took 10 minutes of circling the last known cairn to find the next one which turned out to be hidden by new growth. (This was before the very wet spring of 2005.)