This is a multi based on a ridiculous series we were stupid (addicted?) enough to try and complete in our old home town of Portland, OR by an infamous hider by the name of MMmm!! He was sadistic enough to send Portland area cachers all over the Pacific NW (and sometimes beyond!) collecting phone numbers from various phone booths around the Portland metro area. I DO NOT intend on making this one that difficult!
All you need to do to find this multi is go to the posted coordinates and gather some info- a phone number. This number will be ABC-DEF-GHIJ. Plug the info into the following formula to find the final location, which is a ten minute drive away.
N (F-1)(A+2) F(I-1).HJJ W (G+1)C(B+3) C(H+1).(J-3)G(D+1)
You can validate your puzzle solution with certitude.