Given that the thread title is alternate colonials, I'd say have more immigrants to New Sweden, possibly spreading to all of the Delaware Peninsula. Britain still comes to control the colony, as per OTL, but stronger Swedish presence leads to a somewhat similar deal with the Swedes as the Germans and French. I don't think that would butterfly the American Revolution (certainly wouldn't touch its root causes), but it's be interesting to which side the Swedes join, and its long term impact.
Maybe some sort of Amish analogue (not in their unique social aspect)?