Washington realized he couldn't put together a duplicate of the British Army (much of which consisted of Hessian mercs, in the first place) and beat them at their own game. He realized he just had to keep them on guard duty and stay out of their reach until he had some advantage that his adversaries didn't recognize. And nowadays and from now on (since the 1970s), no US general will ever outrank The General. :^)
Hear Hear ! I think Washington is deeply under appreciated as a general!