You'll find a few in Barnegat Bay, mostly closer to the inlet, and mostly Old Squaws; a few scoters later in the season. Close to the inlet on Great Bay can be good if you get to know it in calm weather.
Mile or two out in the ocean is usually enough, but beware of the stripper fishermen who aren't expecting to see you out there and won't see your decoys...have had them run right through them. Refrain from instinctively shooting at their boats as they whip by out at 40 mph, throwing a murderous wake and carrying off a string of dekes.
We go out in a 17' TDB, or a 19' Whaler, choosing the weather and inlet conditions very very carefully.
"There can be no greater issue than that of conservation in this country." Theodore Roosevelt