burnt out, ready for a month reading books on a beach

Ko Samet or Ko Chang without a doubt.

Ko Lanta, Last Beach

Ko Phayam.
In fact your post has made me think that i need to disappear there for a while.....................

somewhere like Ko Kham or Ko Wai, both small Ko Chang satellite islands with no nightlife whatsoever, no canned music, no internet, no nothing except a restrauant, your hammock, your bungalow and the beach. There's inumerable other options like this. I'm off there in a couple of days, but a month would be too much for me. Five or six days is fine.

definatley ko chang, once there you can choose the level of isolation/peace

Koh Phayam or Ko Chang - Andaman sea side ... Ferry boats from Ranong .
No roads , no cars ...still cheap acomodation ...
Koh Phayam is little more comunicate than Ko Chang . In K Ph you can rent motobike or have a ride for 50 Bths . A couple of internet places and mobile cover in the village of Phayam ... Check # web site for both of the islands ... if you really need the Robinson trip try
KOH KHAM ... The satellite of Koh Phayam . It is a small private island from which you can walk at low tide to Phayam village . 30mn . Check their Web site : www.khamisland.com<BR> Anyway you can trip and hop around - probably a full month in one place shall be a bit long ...

koh phayam also, Vijit's Bungalow, quiet, inexpensive accomodation, beer and tasty food. he may still pick you up at the pier.

Koh Chang- plenty nice quiet places still to be found.Not far from Bangkok,not that much traveling.

i would say koh kham ie. #6, it's near koh chang (trat) and it's gorgeous and peaceful