[Tim Baird]

This solves it!

Dave did work down at Mt. Erebus with the Dante project. As you may or may not know, the Dante robot was copied visually for the robot used in the X-files episode "firewalker" which originally aired on 11-18-94.

Now, looking at the production number of that episode, it's 209.
So, switch back to the other coordinates, which point back to Boston. Go to the nearest train station, look for locker 209, and the combination for the lock should be the aforementioned 3 digit number. The next clue is inside!

Run quick! Find the clue!