There are a few Enterprise offices along Rte 18 in the Old Bridge/E. Brunswick area. I don't know if they'd let you leave your car.

Usually I leave it at Avistar for trips of 9 days or less and use a limo for longer trips.

Note that some limo companies charge extra for those extra early pick ups.

I just got back from an 8 day rental using Avistar and it was about $120 using my corp discount (AAA is almost the same rate). Sometimes this is the best alternative.