Originally Posted by Diplomatico

If your layover is in the restricted security area of BKK (and I suspect it is) then there is no deal to be had at BKK.

The main entrance to LM faces Loi Kroh Rd (it's basically at the intersection of Loi Kroh and Changklan.)

Walk out the main door onto Loi Kroh Rd, turn right. It's about half way down the street on the way to Thapae Gate, left hand side of the street as you walk toward the moat. Address is 34/4 Loi Kroh Rd. (There's more than one location but that's the closest to your hotel.)

Super Rich Money Exchange (Chiang Mai)