Weehawken, NJ. Backdrop would be midtown Manhattan. Take route 3 towards the Lincoln tunnel, then take the last exit before the tunnel. Go through the stoplight to the bottom of the exit ramp and make a right. Then take the next light and make a left (police station on the corner). Wind your way under the overpass to a stop sign. Go straight through the stop sign towards The Chart House (restaurant). When you spot the restaurant on your left, pull into the parking lot and park somewhere on your left (facing north and the Manhattan skyline).
If your shoot is this Tuesday night I can go with you.
Second idea - there is an overlook spot off route 78 in Bridgewater, west bound, just before you get to the 287 exit. Go to the top of the overlook, and take pics - you may not have the right angle to catch all of the Raritan Valley behind you, however you'll have plenty of night sky - black backdrop on a white car.

Plus this is a lot closer than the first idea.
Bridgewater mall, upper parking deck. The hills of Bridgewater would be behind you. Maybe a twilight shot with just enough light to illuminate the hills.
Lots of horse farms in Far Hills, just off route 202. Not too far from you. White picket fences, wide grassy fields. Thats better for daytime shots though.
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