Dude, that is awesome. I like reading and hearing stuff like this. From what you described, it sounds every bit like Friday night HSFB down South.
The playoffs are the best. I like going to the games, even if it means a road trip. The crowds are larger, the statewide media come out, and, the state's university coaches are there scouting. Plus, the leve of play is so much better.
The biggest rivalry that I know of in eastern NC is Scotland Co-Richmond Co. Richmond won something like five 4-A titles in six years not too long ago, and, Scotland has won a couple recently. Its nothing for their games to draw 25,000+. In western NC, I think its Waynesville Tuscola-Canton Pisgah. Crowds over 20K are regular occurences there, too. There may be others, but, those are the ones I've personally read or heard about.
Just an aside, a few weeks ago, one of our local kids received an offer from, and, committed to, Penn State. Penn Freaking State. I never in my lifetime thought any kid from here would get an offer from a school like them.