I tried walking (and some running, but no fast travel) from Concord to Bunker Hill, to the Slog. Played out the same. Was able to completed the Bunker Hill stage with out issues (other than the young girl sitting and clipping into some barrels). Continued to The Slog, and got stuck in the same place. Restarted from a save prior to completing Stage 1. After receiving the second quest, I decided to mix it up and went directly to The Slog. Did not change the results. Given the number of bugs I've been seeing (The 4 southern most settlements aren't connecting to a trade route, all the plots on the included full size Egret Tours Marina city plan are all either duplicating, triplicating, or quarduplicating and refresh doesn't help, as well as power issues and rewiring some settlements multiple times, and the long save times). I'll start a new playthrough in 6 months or so after a few more patches have been released.