Nothing was more evocative in our trip to Xinjiang of the real old Silk Road than our visit to Tiemen Guan. An hour or so from Korla, it's not a big tourist site, but you can walk down the old oasis road beside the river probably as far as you like--we stopped about a kilometer in. It's a trail through the riverbed beside the mountains, and you can almost hear the camel train.
Perixte
Climbed it a couple of times before 2006. At the top is a statue related to a kind of "Romeo and Juliet" type story. You can climb to the top from the front or back. I've heard it said, "If you don't climb to the top you'll regret it; if you do climb to the top you'll regret it even more!" It's a lot of stairs and not really any shade along the way. I can't remember how long it takes to get to the top, but I don't think it was more than an hour?