Welcome Tony. For what you are looking try Phuket.. Stay 5 days in Kata, then Karon, then Patong, then Phuket city with a few extra days for Samui! Krabi, while very nice, is worth a visit but not sure if it will be up to your friends expectations.
Yes, I did read that you have been to Phuket, my point was you can stay in many places on the island, have a blast and still do all the things you are looking for!
