In reply to mugglewump:
Staying in Ao Nang is a good option - especially if you are happy riding a moped. You can take day trips over to the Railay and Tonsai crags, plus also ride out to some of the newer crags that are close to Ao Nang. I personally thought that Chong Pli was a great spot. Also, you can access Vinland walking from Ao Nang, plus a handful of other crags with a short ride on the moped. Consider a few days on Koh Yao too - much quieter over there - possible to ride over on the scooter (you will need to lift it on to the boat) - amazing climbing, especially the Mitt.
Enjoy! I will be there from 25th Jan onwards so get in touch if you are still there at that point and we can meet and climb.