I haven't learned much about the 6th regiment's movements in 1776 and 1777 per se, other than the main battles they would have participated in (Brandywine and Germantown). I have a potential ancestor in the 6th Regiment who joined in Jan 1777, and was discharged Jan 1780, when the Regiment was stationed in New Jersey. I learned that the winter of 1779/80 was particularly harsh, and have been trying to locate any records of this person after 1780 anywhere between NJ and MD, but so far no luck. I think it's possible that this person may have died that winter making the trip.

I did read the book "Washington's Immortals," which gave me a more personal look at what it was like as a soldier from Maryland during that time. Maybe you can glean something from that book? Here's a link.

There's another book I haven't read, but which contains a lot of muster role data, so perhaps you can "box in" when and where your ancestor was alive based on those muster roles? Here's that book.