Harbinger - I hunted (and plan to hunt) Sawmill creek weekdays, when I can. Msg me any questions you have! Yes, you definately need a boat! Question is, what kind of boat do you have?
I heard that it was full on opening day last year - not so busy during the week and later in the season, but I always see ducks (don't necessarily get to shoot them though). Tides are brutal, over 6 ft. You don;t want to get stuck on the mudflats by the NJ Turnpike at low tide! There are 2-3 ditches which keep their water at low tide, so all is not lost.
I heard from some of the guys I met there that its mostly guys from the Bergen County Duck hunting club (or something like that) that hunt there. Some guys come from as far away as PA to hunt there.
duck hunting IS all its quacked-up to be!