The other thing I want to mention is actually about the maps. This is mostly interesting for places where the generally very good maps have some issues.
Firstly, on the Burnside Takes Command map (and others that show that area), there are no bridges at Waterloo VA or at Rapidan Station. In reality there was a bridge at Waterloo VA and another at Rapidan Station; the latter was only destroyed in 1863.
The first has only minor effects on the course of the fighting (it means that if it rains in the first couple of turns of the first Burnside Takes Command scenario then it's possible for Burnside's forces to cross the upper Rappahanock and ready themselves north of the Hazel).
The second has a more major impact because the lack of rail bridge means that the rail line is "broken" - since Longstreet's forces in the first Burnside scenario start at Culpeper then it might be important for them to be able to rail down towards Gordonsville, and in addition to that the time taken for the Confederates to burn the bridge might be significant. If the Confederate player leaves a division behind to burn the bridge and it
doesn't rain the next turn, they're vulnerable, but if he
doesn't burn the bridge and it
does rain the next turn the Union player has a way to cross the Rapidan.
The second map to highlight is on the On To Richmond map. I'm going to show a bit of the map:
The problem is those bridges over the Warwick. Not all of them actually exist, in fact only one of them unambiguously does.
There is a bridge at Lee's Mill.
There is a dam at the Garrow Ridge, which
could arguably be represented by a bridge since this dam was actually destroyed at one point (and dams in GCACW are indestructible). Historically however it was considered that Garrow Ridge and Wynn's Mill could be defended by one brigade early in the siege, and I would say that it might be more correct to put the "bridge" (dam) one hex further northeast.
And at Wynn's Mill there is simply no bridge or dam crossing at all; the area was inundated and it was a ford during good weather and impassable during heavy rain. This should be a ford.
This all has a significant gameplay effect in terms of how much the Union commander can make progress during rain turns, as rain turns are especially frequent in On To Richmond. In fact during April it's more likely that a Minor River will be unfordable than not, and it gets worse in May.