You haven't mentioned fort niagra, you did take this? It's the prerequisite for attacking the north. RTI is pretty heavily scripted through episode 2.
Flavius Gonzo asked if it's worth bothering with, you don't learn much more that's essential except episode 3/4 give you a preview of how the later game techs work. and completion is how you can play as the yankees. Don't think I'll play as them again though as it starts pretty late game.
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