Charlotte is a big town and can get very busy. I would first suggest that you plan your travels through the Charlotte area to avoid morning and afternoon rush hours. While I am in Michigan, my daughter lives on the north side of Charlotte in the Highland Creek area.
We normally stay with my daughter when we travel that way, so I am not extremely familiar with RV parks in the area. There is an RV park in Concord right by the speedway (east side of Charlotte). North toward Stateville is another RV park, I believe a KOA, and a nice RV Resort on Lake Norman also north of Charlotte. The closest I know of to downtown and the NASCAR track is the one in Concord.
If you would add your RV information to your signature it might help others make better suggestions for you.