I spent three weeks there, I pretty much just headed north along the Burma boarder. There was fighting at the time, but Thai police are very careful about tourist. Make sure you have your passport on you at all times. I got stopped and checked, but there where two other people on hired motorbikes with out passports, they could not get through the check point and had to turn around.
It is a beautiful ride, with great scenery and refugee camps that just blow you away in the scale and the construction of the buildings.
I really recommend heading up to northern Thailand!
Just refer to GT-rider.com their maps are fantastic and Dave who lives in Changmai has all the answers.
let me know if you have any particular questions!
For more information on my adventures, please visit either of the following: