Thailand forum

You might want to look at the beaches up the northern east of phangan. Utilise the search engine here for your research on " getting to phangan", works pretty well.

Regards

Update to my previous post.

Although you'll still have to apply for a 60 tourist visa if you want to stay for more than 30 days in Thailand, there's a possibility that you can extend it for up to one year according to the Phuket immigration site. See: http://www.phuketimmigration.go.th/visa/visa-en.php

The other rules I mentioned such as double or triple permits still applies though.

One other thing worth mentioning if you happen to go to Phuket is that you might notice an immigration office on the beach road in Patong. Here's the Google Street View of that office: http://goo.gl/maps/Dmsyo

If you zoom in on the white notice, you'll see this: "Visa extension, Re-entry permit, Notify of staying longer than 90 days". This might give you the impression that you can extend your visa here instead of having to go all the way into Phuket Town.

Unfortunately though, that's not the case and this office only handles Non-immigrant visas. I made that mistake myself the first time I wanted to extend my own tourist visa and had only two days left before it expired at the time, so I was in a bit of panic that day.

For information on Bangkok to the islands, see this story. bus basically you need a train from Bangkok to Surat Thani and then a ferry to Ko Pha Ngan (perhaps via Ko Samui depending on times etc).

Train tickets can be purchased at the train station in Bangkok (ideally go a day or so before intended departure) or via a travel agent in Bangkok for a small surcharge.

Ang Thong National Marine Park is easily visited from Ko Samui - see this story for more information, including prices of accommodation - the need to book in advance would really depend on the time of year you are going. The tours most frequently go from Samui -- not Ko Pha Ngan as Samui is closer to the NMP. I'm not sure of the practicalities of getting there without taking a tour boat sorry.

For off the beaten track islands in Thailand, the following two stories should be of interest:
Thai islands to lose yourself on
Thai islands for nature lovers

Hope that helps.