Well, the prevailing winds as you mention are SW. So one way or the other you could be beating into it. The current in the delaware canal can be timed and predicted. The delaware river is a long day either way..you'll see both a fair current and an unfavorable one, but I wouldn't base my choice on that.
Depending on how much time you have. You can pick your weather
window window in either direction heading to Cape May, or Norfolk/Portsmith. Then pick the best window for the offshore
leg from there. If you're doing it non-stop..then I think odds of a favorable SW wind for the offshore leg would tend to favor the counterclockwise trip.
It always seems that whenever I sail the chesapeake in either direction I have the wind in my face, hopefully you'll have better luck.