A lot of pages about this event say the fairgrounds offers on-site camping. The confusion is understandable, because the Ozark Empire Fairgrounds does keep campgrounds and does accommodate campers during certain events. But NSRA's own entry form for this event settles it in four words: on site camping is not available. It then points entrants at the lodging guide for campground listings. That is the sanctioning body speaking about its own event, so it outranks a general fairgrounds policy.
Which makes the answer simple rather than disappointing. You book a campground or RV park anywhere around Springfield, we deliver the trailer there, and you drive ten or fifteen minutes to North Grant Avenue each morning. Spectator gates run 8am to 5pm Friday and Saturday and 8am to 12:30pm on Sunday, so it is a daytime event with evenings free.
No trailer parking or oversize vehicle guidance is published for the event either, on the entry form or the spectator page. If you are towing a show car on a trailer, that is a question for NSRA before you arrive rather than something we can answer for you. What we can tell you is that your rented trailer will not be anywhere near the fairgrounds, which removes the problem entirely.
"Rented a Class C for a family trip to Silver Dollar City. The RV climbed the Ozark hills with no problem. The kids loved the bunk beds, and the pickup in Springfield was super quick."