Sounds like this is your first trip to Maxton. Mine was last year for the first meet, and I got TOTALLY hooked. These are the nicest people you'll ever know.
As far as security - the track is in a VERY rural location, and down a small lane - it looks like they made a mistake and put the sign at the wrong location. No one would wander in unless they meant to, so it's unlikely wandering teens or other "crooks of opportunity" would even see or be in the area. As Slim said, a number of folks camp there, in everything from pup tents to luxurious motor homes, and I'm sure they would notice any vehicles that entered in the middle of the night, and they'd get involved. If you were concerned, you might want to leave your stuff near the campers.
That said, I took my car and open trailer last year (October), and left it out while I went to the Pine Acres Lodge (sort of unofficial Race Headquarters). Nothing was touched, even though I forgot to put the hitch lock in place. And I was parked far from the campers. Doubt you would have any problems, but, of course, there are no guarantees.
A note about the Pine Acres Lodge. The rooms are large and quite clean and the prices are reasonable, but they have NO no-smoking rooms (but they were thinking of changing that). I take a giant bottle of Febreze and go to the room first to squirt everything (drapes, beds, carpets, etc) and by the time I get back from racing and dinner, it's not too bad. If you would like no-smoking, I suggest you request it when you call for reservations, and bring it up when you check out. If they get enough feedback, maybe they'll make some rooms for us no-smokers. If you're a smoker, you'll love the place!
Another FYI - all lodging and nearly all dining is in Laurinberg, about 10 miles or so from the track. I went to all but one event last year, and have yet to see Maxton. I may do a sight-seeing trip there just to say I've seen the city light (singular, I'm guessing).
See you at Maxton Dan