hi, i spent my gap in thailand on kpg. re weather, dont worry bout it, the rainy season in the south just means you get some for about an hour in the afternoon and in the evening, and man, it is NICE! such a relief. i went out at the end of the hotter months and it was unbearable to start with. i dont think you need to avoid any area really, maybe just not the deep south at the moment. especially as you are travelling together. just use your common sense and dont get involved with drugs. everyone gets caught in the end, whether its their first time, second, thirtieth whatever. thailand is not the place to experiment! recommendations - you have to go to Koh pha ngan. most people just go there once each month for the full moon parties, but the island is so beautiful and there is so much more to it than that. koh tao is also stunning especially for divers. really, it's easy to travel round, and you'll have a brill time. good luck!