Dont worry about garages! There are planny available. If i remember right, they are about 30$ for a day. For the whole weekend is about 50$ 2-3 people can fit there easy and the price will be splitted up. Power included. But if you have a generator, bring it just in case! Sometimes the breakers tripping because too many warmers plugged in.
If you have EZ-UP bring that. Cheaper. Also get yourself some carpet or bubber mat. Pit road is paved but in between that hard sand and grass spots. You dont want to clean that off from your hot tires all the time. You can cheat a little and set your tent half way on the paved area and put your bike under longway. If you have 2 bikes,...oh well.
This year we racing only on Thunderbolt circuit. Its also a clubhouse there, with nice showers, buffet with track food /burgers, hotdogs, sodas...etc/
Also a nice tower in the main straight, from the top you can see almost all around the whole track. So if you want you can bring your whole family they can watch you racing and have fun.
One more little stupid thing....If you want to leave the paddock area with your pitbike, it must be registered /they saying/ but at least you must wear a helmet. Basically if you leave the pit area you driving, riding as on the public road. Little thing, i just telling you to keep it in your mind thats it.
You will love NJMP! Once you try it you will see.
Dont worry not as bad as it sounds like ;)
See you there!