How to reach Crystal Caverns
Crystal Caverns is located in the center of Eastern Wastes. Inside the small orc fortress you'll find a shed-like structure in the back which inside will have a small crystal object you need to click on (shown in the screen shot below) that'll zone you into CC.
The hardest part of reaching CC is getting to East Wastes. Depending on what expansion it is for you will most likely determine your route. If it's PoP you can take the PoK book from The Great Divide. Those of you reading this while still in Velious/Luclin or on P99 will need to get a Wizard/Druid port to Great Divide or Iceclad Ocean.