Please help ive been looking for hours and have not been able to find anyone who has had the same problem.

I finished the mission hunter/hunted and had no issue with it so i started the molecular level by fast traveling to railroad HQ and as soon as the loading screen is over my game crashes. I have tried traveling to the old north church in order to enter the HQ but as soon as i walk to close to the church the game crashes. I reload a older save and did hunter/hunted over again to see if that would fix it but i got the same result. I can do anything else in the game without any issue but as soon as i approach the church the game crashes. I really don't want to start over because i am level 50 and have been saving the main story for last and i cant continue with the main story without entering railroad HQ. Any help would be greatly appreciated and thanks in advance.