FTR I have not spent a whoole lot of time in the south, avoided Phuket mostly, but do have a soft spot for Railay as I went there in 1989 before it got developed, so have tended to just go back just to Railay, but have a feeling it might not be the best spot for Loy Krathong - though if anyone reading this HAS celebrated LK on Railay I'd be keen to hear your experiences.