HCR#1: September 17th-20th
It rains on September 17th. Reno leads a grand assault against Lee in Frederick at dawn, 29:26, +0ratio +0arty +1assault -1tac -1rain +2 flank = +1/0 1D/3D result. Lee voluntarily retreats to the mountain pass NW of Frederick. Couch takes Frederick and secures the depot. Sumner's II corps is sent through the Catoctin Mountains at Jefferson, heading for Harper's Ferry. Stuart pulls back to guard the Catoctin creek crossings. Both sides are content to rest their remaining units after a hard fought previous day.
The Confederates miss out on more easy VP by not being able to destroy the depot. Lee's forces ran out of fatigues on the 16th to do it and the Union won the first initiative on the 17th. The ANV has been driven from the field and is about to go out of supply. At this point a marginal Confederate victory is slipping away and the Rebels start playing for a marginal Union victory.
The weather clears on the 18th. All Confederate troops are out of supply, while Union troops are in supply. Lee and Longstreet's divisions guard the Catoctin passes near National Road. The Union II and V corps cross the Catoctin's near Jefferson, while the I and XII move up to the east side of the Catoctin's near the National Road. The IX and VI corps rest near Frederick. In the only combat of the day, Lawton's understrengthed division (3MP) is routed by the II corps (2DR*/a). The Confederates attempt to rest and forage but only AP Hill and JR Jones forage successfully. The remainder of Jackson's command and all of Longstreet's are out of supply.
On the 19th, Lee continues his retreat to Washington county. Longstreet moves his corps to Turner's gap. Poor movement rolls and the OOS extended march modifier result in the 3MP lost to straggling. Jackson covers Crampton's Gap. The Union pushes up to the gaps: I, IX and XII to Turner's; V, VI to Crampton; II to Weaverton. Jackson begins to pull back to Harper's Ferry near the end of the turn. The Union is not eager to press the Rebels in the passes so no combat erupts.
The 20th sees Lee continue to retreat. Longstreet moves his out of supply units behind Antietam creek; Jackson pulls back to Harper's Ferry. The AoP pursues cautiously and a double-1 initiative ends the turn early.
At this point the Rebs are 4 VP shy of a marginal win. With several out of supply units, the only way to achieve such a victory is reckless attacks against the Yanks. The Union is moving cautiously to prevent isolated and unsupported divisions from being targets. It is pretty clear that the 21st will see the two armies stare at each other across the Antietam Creek, so the game is called: Union Marginal Victory.