78silversc:
There are two indoor Kart places I know if in Central and North NJ: one in West Princeton and one in Hanover. I haven't gone to either of those, but the NNJR PCA region in planning on holding a social in the West Princeton place on March 30th. (Not on our calendar yet, but in a few weeks, check out:
http://vista.pca.org//nnj for more info. )
The Hanover place is called Funtime (IIRC), and is located on Rt. 10. I know of some people who have attended there, and they seemed to like their setup.
There used to be an excellent indoor karting place on Rt. 17 in Ramsey: Speedway 17, they called it. Closed down a couple of years ago, but the place was a blast! They had two ovals: a kiddie oval and a grown-ups one. The karts were propane powered and could move quite well. Not sure why it closed down: slow business or other. I know my bro-in-law had to go to the emergency room after a few laps in their gokart: the soft skin around one of his knuckles caught a sharp piece of metal in the kart! (Obviously, they weren't that safety minded there!)
With the recent growth in popularity of motorsports in the USA, and the idea of "if pros go-kart in the off-season, so I should too" mentality it seems like your idea is a good one.
Hope this helps,
-Zoltan.