February is an excellent month to visit Thailand. In feb March 2003 I just had 1 drop of rain in Phuket and Koh Samui. I have also been in Phuket in May and December, and as far as I am concerned february was the best time.
Phuket was not to crowdy and weather excellent.
Travelling in Thailand is not dangerous according to me, i never experienced any troubles. i only did one organised tour and than you do not have as much freedom and you are stuck to the tour operator schedule.
I also book most domestic flights in Thailand direct in the airport, it's a lot cheaper, no go between fees. Only sometimes you need to book an extra night in an hotel or wait a few hours. If I have to wait a few hours I just drop my luggage at the airport and take a taxi to the city centre.
I have never been in Pattaya so i do not know anything about Pattaya.