I had some local volunteers who were going to pretend to be traders. They were going to get in, hold the gates, and let my warriors storm out of the woods straight into the fort. If things went south or if we couldn't take the fort by force then we were prepared to fall back to a series of prepared ambush points and bleed out any pursuers. I wasn't too concerned about any patrols, since we had our warcamp right on top of the fort without any real risk of detection. The season wasn't too big of a deal either, as we were going to attack just before Spring and we had local Natives in our party who knew the land.