Just so you're aware, it's about 550 miles between New York City and Cedar point, or maybe 12 or more hours of driving in an RV (plus time for stopping). The time would depend a good bit on where exactly in or around New York City you're starting from, and what time of day you're going through the city area; but in any case it's a long drive to Cedar Point. (Similar concerns apply to getting to North Carolina; it's a decently long distance there.)
There are many fine, if somewhat smaller and not quite so well known, amusement parks rather closer to New York City. Knoebels (Elysburg, PA) is a fantastic, somewhat smaller, traditional park with a campground on site, which Cedar Point also has; they don't have as many roller coasters as Cedar Point by far, but the half dozen or so they do have are excellent. HersheyPark (Hershey, PA) might be the closest thing to Cedar Point in terms of the number and variety of roller coasters, and they do also have a campground associated with the park. Kennywood (in Pittsburg) also has a good many fine coasters, including several classic/antique ones, all in great shape, but there's rather a dearth of camping in the area unfortunately. Six Flags Great Adventure (in New Jersey, kind of between New York City and Philadelphia) is closer to New York City and also has quite a few coasters and other rides.
I would try to avoid driving a motorhome through New York City if possible. I actually would try to avoid driving any vehicle through New York City, especially to tour the city (rather than just pass through on the expressways, which is daunting enough), but doubly so for a large vehicle like a motorhome.