Off season the parking and walk are easy. Fall is best, water temps are up, the tourist are gone and the tropical fish are in. There is even a wall/curb just the right height for putting on your tank. The entry on the inside of the jetty is a shallow beach but I would not do this jetty in anything but flat seas, the surge on the outside will put you into the rocks before you see them in the normal vis for here.
I believe this is a private beach club so don’t litter, that got divers blocked from easy access to the Dual Wrecks :(
More info at NJscuba.net http://njscuba.net/sites/site_allenhurst_jetty.html