It seems there are a lot of issues with this quest. I currently had a similar bug: not at the end but at the beginning of the quest, where the game would crash when I tried to travel to the Warden Forward Camp (start of the quest). For me it resolved itself by simply restarting the game until it would no longer crash. Maybe try saving as close to the end of the quest as possible and restarting the game (therefore reloading) to see if it resolves the issue. I'm not an expert on these things but maybe it helps...? I just hope they fix this questline asap.
