You know asking about a place to shoot near Trenton - you're just teeing that one up, right?
hahahahahahaha. I'd say anywhere IN Trenton!
I grew up in Hopewell. Sourland Mtn sport club is long gone, don't know if Sohiwe deer club outside Hopewell still has a range or if they even still exist. They used to have a very quiet little range up a ways behind Hillbilly Hall, don't remember the name of the little road there off Greenwood ave. Probably have to be a member though.
I have good friends who still live in Lambertville; I'll ask if they know of anything in your area or out toward Ewing, Hopewell, Pennington etc. I assume you're looking for somewhere quiet and out of the way.