TWafer:
I have only limited experience with NY and NJ law enforcement and don't know how picky they are about weights and DOT rules but I don't think you have a lot to worry about. I don't think you are likely to get in legal trouble. If I correctly interpreted your post your truck is plated for 18k and so is your trailer. That says your equipment is plated (ie tax paid) for 26k. If your truck weighs 6k, your trailer 4,500, and the equipment 14,000, your gross combined weight will be under 26k. If you drive slowly and carefully, your truck and trailer are in good shape, good tires, trailer brakes and brake controller working, lights working, safety chains attached, breakaway brake switch attached, proper hitch, etc, I don't think you'll have any problems. Make sure you have the truck and trailer registration slips, proof of insurance, dated proof of ownership for the piece of equipment you bought, and stop at any scales you cross.
Technically you are commercial and required to have a DOT physical card, reflective triangles, fire extinguisher, and a log book but if you can demonstrate that you just bought the equipment and are simply delivering it to your home yourself and don't normally cross state lines I doubt that a DOT cop will ticket you.
If you own the truck, trailer, and equipment you are "commercial" but are not "for hire. " DOT troopers usually, but not always, take a harder look at for-hire drivers than a contractor or farmer who is hauling his own over a relatively short distance.
Harvey
Attention: TDR Forum Junkies 
Trying to decide on whether or not to try this. I bought a piece of equipment that supposedly weighs 14000 lbs. I’m in central NY and its 255 miles away in NJ. I have my 95 Ram as below along with an Eager Beaver tag along (not gooseneck) 9-ton trailer. It is triaxle and good brakes and tires on it. I’ve tried to find someone to haul it for me but have so far struck out. I’ve hauled 14000 lbs before but not for that distance or out of NY State. My main concern is, what kind of legal trouble am I likely to get into and what can I do to avoid as much as possible? :{ Trailer is reg at 18000 and so is truck. Truck weighs about 6000 empty and trailer about 4500 empty. No way to be 100% legal I'm sure, 
but how bad can I get hit? :-{} I was thinking maybe doing it on Easter Sunday morning figuring not many would be out.
