Know this answer is late, but hey... just ran into that oddity myself after buying the game on the last steam sale

and running around mapping DC wasteland. I have gotten there, but only through the use of console commands. Might go continue to look for a way in when I get bored or something.
1. Go to Takoma Industrial (sp?), turn collisions off in console (tcl) and then put a marker on world map at the Commonwealth Observation Camp. Then just run toward it on the local map. Does not take long. Btw, a group of feral ghouls are in the area also. They immediately attacked even though I was still inside a wall and killed me. Learn me to go wandering not in god mode.
2. After I got there, I found 2 notable corpses laying there in the screaming yellow radiation suits. Jason (000c9ae3) and Isabella Proud (000c9ae4) which player.moveto works with. With those codes its from the Fallout base game, not an addon because fook2 for me is 08 and 09 prefixes.
Hope someone else does not waste the amount of time I did trying to get there.