Dear Gjord,
As I living in Thailand I would like to introduce you to visit Thailand, the land of beautiful beaches. We have a lot of beautiful beaches such as at the north end of Chaweng Beach on Samui but maybe Samui is probably one of the most expensive destinations in Thailand with very little to see and do away from the beach.
Phuket is one of Thailand's most developed beach resorts. That means there's a wide range of accommodations in all price categories, as well as a few more distractions once you leave the beach. But, that high level of development is because there are a lot of tourists to serve. Phuket is not the place to "get away from it all.â€
Koh Chang (Chang Island) also one of the popular beach of Thailand, I usually take a vacation there. There are beautiful beaches with white sand beach; once you visit there you will never forget about the nice beaches of Thailand. As you mention that you have two kids, you may look for Kai Bae Beach (Haad Kai Bae) is located south of Khlong Prao Beach It is an almost 2.5 kilometer-long beautiful sand beach, which is partially lined by over-hanging palms and broad-leaved trees. Most of people with kids never had any problem to stay at this beach because the water is not too deep and a lot of resorts are available for you to stay such as Siam Bay Resort, Chang Park Resort, Kai Bae Beach Resort, Seaview Resort and many.
Then on the way back to Bangkok you may visit the popular place like Pattaya, the land of beautiful nightlife.
For more information about Koh Chang (Chang Island), visit http://www.kohchang.in.th there is lots of good information waiting for you to find about vacation on Koh Chang.
Cheers,
Travelor