Well, after the battle of Bunker Hill, I had Washington and his small army plus the garrison in Boston. I combined both and marched immediately north to take Maine and the remnants of the Brit field army. After doing so, I left some of the troops in the capitol of Maine to keep order while it stabilized and moved the rest back in between Boston and Falmoth(?) to cover them. A couple of turns later, the entire garrison of Albany came out to raid my towns in southern New England, so I killed them with the field army then took Albany.

The Iroquois did not enter the war against me at this time. I did some dancing in the north until I learned how to cover the Maine towns against raiders from Acadia and New France, then built up the field army to max strength, and then took Philadelphia from the British. Once I'd rebuilt the army from the casualties I took I shifted north to go against Acadia while leaving a large garrison force behind, and the Iroquois started building up on the border. Philadelphia could recruit 4-5 units per turn so I bulked up quickly and left a half stack sitting near the border blocking their route in.

I don't know if this kept them out of it, but they didn't declare war until after I'd taken Acadia from the British and was going after Quebec, by which time I had a full field army in the north as well as a full army in the south plus a half stack of extras.