Some more observations:
(1) In the OR and in the McClellan Papers (LoC), there is no backchannel correspondence between McClellan on one side and Lincoln or the Cabinet on the other. GBM's scant official exchanges with Cameron hold little interest. His correspondence with Scott is actually accusatory; he wants guidance, he wants orders, and he wants federal funds. One has the impression that McClellan is isolated in the grip of his patron, Dennison. He reaches out to Washington but there are no answers.
(2) Once he heads a multi-state department, it seems odd that the other state governors do not step into similar relations as Dennison has with GBM. They work him through Dennison.
(3) Just as McDowell-Franklin is liquidated by virtue of a military offensive, so the invasion of Virginia ends McClellan's career as advisor, organizer, planner, and strategist to the governors.
(4) Scott's refusal to allow GBM to link up with Patterson during Scott's first coordinated offensive could have been the fruit of a tidy mind honoring department borders or it could have been slapped down as an inopportune attempt to escape Dennison's patronage by placing himself under federal control.
(5) With GBM's arrival in DC, all the armies' three month men - the experienced part of the army - have melted away.