I had very little luck working with NJ dealers when shopping for my 1500 Denali. Lots of NJ dealers are charging MSRP, because these are not sitting on the lot for long. I would up using Star GMC in Easton, PA. You will still need a supplier code for the best discount and the only real rebate is $1750 for GM loyalty, so without supplier & loyalty, you will be looking at the kind of numbers you are getting quoted.
You should be able to get pretty close to reproducing my deal only real change would be the MF up slightly now.