Get ready to earn that D/T rating! The posted coordinates will lead you to a phone booth that has the info you need to get to second stage (a phone number). You will need to bring some "tools" to figure out this phone number. Once you grab it, let that number equal ABC-DEF-GHIJ and plug it in to the following:
N: A(G+1) C(F+1).(H+1)B(F+1)
W: HID ED.(J+1)EE
These are your coordinates for the next stage which is, naturally, another phone booth. To make sure you are correct (since I can't add a checker for you) the checksum of the coordinates should 35 for the north coordinates and 26 for the west coordinates. Once you've verified your coordinates hop in the car and find it!
Once at the second stage, you'll need to do the same- gather the phone number and let it equal KLM-NPQ-RSTU (notice that I omitted the letter O). Plug that info into the following:
N: KR (N-2)L.L(M+1)T
W: (Q-1)L(M+2) LK.(L+1)NL
Once you figure that one out, you can use the checker below to make sure that you must actually... drive... all.. the... way... THERE. Good luck and happy hunting!
You can validate your puzzle solution with certitude.