How on earth do you get there? It seems to be at the top of the mountain, but I can't find a passage.

There is a passageway up the mountain from Depending on how you fight, I'd take lots of with me. I thought this quest was broken until someone here helped me. Good luck!

You have to get to the road that leads off to Jacobstown. The one with all the trees that have actual color. Then follow a split off the path early on the way to the town.

If you look closely on the map you'll see there's a small road leading out from the road to Jacobstown.

you have to go as far north as you can, around the mountain, and follow the road down to Jacobstown. The ranger station is off that road, you can't get there by going over the mountain (I tried for hours, kept running into invisible walls and cazadors)

I haven't been to Jacobstown yet so I got to Station Foxtrot without going to Jacobstown. It was a struggle though. I kept climbing and scrambling and jumping over rocks and finally ended up in and then took it from there. I'm glad to read there's a better way for next game because I don't know if I could do it again by mountain climbing.