I shoot with a D600 and all the above advice are good to go.
Just a couple things to add.
Yes, you should be shooting in RAW, however, if you are shooting in JPG or "RAW + JPG" mode, make sure "Active D-Lighting", "High ISO Noise Reduction", "Long Exposure Noise Reduction" and "Auto Distortion Correction" are all turned OFF. Any of those settings add to the processing time, and prevent you from taking another photo until it is done, especially when you get to the 5-10 second range and above. This is true for most modern Nikons. I had to do the same when I had a D7000.
While my aperture is at f/11 and ISO 100, I also use a 3 stop neutral density filter to prevent bright fireworks from blowing out. This is mainly for the finale, as it is super bright. Lots of people shoot without it. It's a preference.
Locations:
If you are brave, try shooting from the Hub. This shot is right next to the Partners statute. The area is heavily crowded; people and kids will bump your tripod. You will have to get to this spot super early. This was shot at 16mm and 13 seconds.
One of my earlier works. No ND filter. This was on mainstreet, just outside of the hub, on the bridge. This was at about 24mm, but should have gone wider. 4 seconds.
If you are a DVC member, you can shoot from the Top of the World Lounge at Bay Lake Tower. Much less crowded because of the DVC restriction. Also you can indulge in libations as you enjoy the show. 24mm lens ans 21 seconds.
This is from the beach at the Polynesian. It's very laid back here, less crowded. About 35mm and 12 seconds here.