Ok, first impressions : I looked at everything superficially, first great job at putting all the armies around.
Some things that hit me on the first look : I'm not sure what Beric is doing in crannogmen territory, he could be more to the south, or maybe not in the scenario at all. It's going to be tough making him act rationally.
Also you made a choice to not differenciate Joffrey and Tywin. Tywin clearly does his own thing in book 2, going west to defend the westerland, not caring about Stannis at all and only being stopped by Edmure. I genuinely don't know if it's a good or bad choice. Maybe Edmure could be vassal to Robb then ?
Also I find some cities a bit underrepresented like Yronwood which is the second most important house in Dorne. They deserve some reasonably good land and a size 2 or 3 castle.
The wall being forts doesn't seem right. Mance's army can just walk right through it.
Robb's army in Riverrun should be mostly horse archers and the eastern part be a pretty big host of foot soldiers.
Those are minor details really, you've built a great starting point from which to make a great scenario.