After I left adventurer's guild I went exploring and SOMEHOW a block is 'closed' behind me where I cannot return to the area with NPCs/Guild/etc to advance the story, I literally have only one way forward and that is into a fight at Roscoe's I cannot win (at best I've taken down the two melee mobs before the archers destroy me). Basically I go back to that 'push' block but it's closed in a way that I can't 'pull' it back out and access that area.
Am I hosed? 2 straight hours wandering in circles with nothing to do except cry in front of this block. Pretty frustrated.

Did you try interacting with it and backing up to see if you could "Grab" it? I'm sure you did, just throwing this out there. I haven't experimented with the blocks so idk if it's something possible.

If you're early enough in the game where the fight is 3 guards, and you absolutely cannot figure out how to win the match, it might be worth loading an earlier save. I know I have checkpoint saves at every save stone I've used.

Just some food for thought.
-Cym