I only play against the AI (I did play a PBEM once, which was enjoyable).
What is the best strategy for the Allies for bombing prior to an invasion when playing against the AI? If I was playing a human, I'd bomb railroads, so the Axis couldn't move troops via them. But the AI doesn't always need railroads to move units up the front. Is bombing railroads a waste of effort?
Is just bombing depots/railyards and ports the best thing to do until the week before the invasion? Then the week of the invasion use Ground Attack/Interdiction on and behind the invasion hexes? Or are there other target types I should hit?
Also, when hitting railyards before an invasion, how deep do you recommend? I usually bomb from the Dutch depots in the north to the Normandy depots in the SW, and as deep as the Loire valley, Champagne, and Liege/Aachen. I do this whether I'm invading in Normandy, around Rouen, Calais, or Holland. Am I wasting bombs, planes, and aircrews?