RAH- I haven't been up to Mae Sai or other points far north in quite some time. I'm surprised Mr. Joe gave up the GH, I thought he had a wife that was either Shan,Wa or some other local ethnic minority, perhaps she runs the place. I know he was dealing in gems as well, I kinda lost touch with him. As for the Karenni if you're heading up to MHS in the next 2-3 months, let me know. There are people there I need to contact.
Rickshaw-Mae Sai is cool for a day, and as RAH mentioned you can go through some parts of Shan state, Kengtung is as far as you can wander, however I knew someone who traveled from the Thai/Burma boarder up to Lashio, but they had made prior arrangements with the Burmese army in order to get there. Also Mae Sai isn't far from Sop Ruk, Chaing Sean (sp?) & Chaing Kong, which you can get into Laos from