What are the key details and tips for traveling from Chiang Mai to Mae Sai and crossing into Myanmar for a visa extension?

Hi everyone, just checking in to report that I had a successful trip on Friday from Chiang Mai to Mae Sai and over to Myanmar for a new stamp in my passport (30 day visa exemption). I arrived in Thailand a few months ago on a SETV with US passport, and then I extended it for 30 days at immigration (at Promenada). I needed to take cheapest and quickest option to get me back to Chiang Mai. So on Friday I took the Green Bus with VIP seats at 8am (arrived 12:45pm) and then 2:30 back to Chiang Mai (arrived 7:45pm). I reserved my bus tickets online at Green Bus website and paid cash at my corner 7-11 and they printed my tickets with a code. It was easy because of the good advice I got in this group, but I want to add a few things: 1) I was advised in this group to pay the $10 USD for one day Myanmar pass rather than 500 baht, because it is cheaper. That $10 bill has to be absolutely pristine condition or they won’t take it. I had to get one from money changer just before the border. 2) There is a -30 minutes time difference between Thailand and Myanmar! My phone changed the time as soon as I crossed over so I thought I had more time for lunch. I ended up rushing back and almost not making it to my bus. 3) If you are late, the song tauw at border will take more than the standard 15 baht to rush you to the station and ignore all the shoppers trying to flag them down! I literally jumped from the truck to the bus as it was starting to leave.

So thanks for all your help! (And particularly to the young guy from UK who helped me at border, if you are reading this!) I’m going to extend for another 30 days at immigration while I wait for my education visa paperwork to come through. Then I’ll be off to Vientiane for a day or two, and will read up here beforehand.