Green Lotus Peak
This cache is a short but energetic workout near the center of town that will give you some spectacular panoramas.
Many visitors to Guilin end up taking tour cruises down the scenic Li River to the lovely town of Yangshuo. If you're not on a cruise, there are very frequent minibuses to Yangshuo from in front of the Guilin train station (cost: Y7.5 [note: this was accurate as of the time the cache was hidden in 2003, it's almost certainly more now!]); all you have to do is wander into this area, say "Yangshuo?" and a tout will magically appear to put you on his Yangshuo-bound bus, a journey of about 1-1.5 hours. (There are equally frequent minibuses from Yangshuo back to Guilin, for the same price and time.)
The trail to this cache begins as a set of concrete steps in the vicinity of N 24 46.556' E 110 29.402' - on the main road, keep walking towards the river until the buildings end and it starts to curve around to the right, and the stairs will be on your left. From here, the path quickly turns into a dirt trail that winds up the steep limestone karst peak known (in English) as Green Lotus Peak.
It's only a 20-30 minute climb to the top, but I use the term climb with good reason. The trail is steep and can at times be so slippery as to be impassable, particularly if it has rained in the last day or so. The terrain rating is an average for the conditions - if it's dry it's about a 4, but if it's really wet then it's a solid 5 stars. On some stretches there are toeholds carved into the dirt...I strongly suggest using them if you need to.
There are some dropoffs that would have quite a negative impact on your health if you went over them, so please be careful and don't rush yourself. I would strongly recommend a decent pair of hiking boots or other good shoes, and an extra set of pants just in case you get muddy. It was wet almost continuously during the week I was in Yangshuo, but perhaps other times of the year it's drier.
The cache container is a small Chinese tupperware-type container, which contains a stash note/log sheet and a few coins from Hong Kong and Macau. Be sure to bring a pen to sign the log, and some extra film for your camera - the view of the river, the surrounding karst peaks, and the town of Yangshuo below you is one of the most spectacular I've seen in all of China.
I've posted detailed spoiler info below, as this is a place that is enough of a workout to climb just once. No matter where your GPS may point you, this cache is not over a cliff edge or any place dangerous to access - I think the coordinates are pretty close, but accuracy in China may not be what you're used to back home.
16-Mar-2013: This cache just had its TENTH ANNIVERSARY. Wow! This is one of the oldest physical caches in China now. THANKS to everyone who's visited and helped out with maintenance and good luck to those who are planning to do so! It's much more difficult for me to visit Yangshuo than in the past, so if at some point it seems like the cache has disappeared again (as it did a few times in the past), I would greatly appreciate any assistance in replacing it.
Good luck!