Try Hugh Bicheno's 'Rebels & Redcoats: the American Revolutionary War', Pub. 2003, to accompany a BBC TV series. There is a chapter on the northern campaign and I enjoyed reading it, one of a handful read on this war.
Mark Urban's paperback edition of 'Fusiliers: How the British Army lost America but learned to fight'. An excellent short account mixing the regimental - a line infantry unit - and the wider war. First published in hardback in 2007. Maybe too tactical?
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