For Norton fans, I will second North Royalton being a great venue. Parking is great (worst case even if there is a huge crowd, there are plenty of spots right across the street at the library, but I'm guessing the sizable school lots will be enough). Plus, there are a couple of places to grab a bite to eat and a drink within walking distance to the stadium and quite a few more that are within a 1-2 minute drive.
Since Norton is the home team, seating will not be an issue. The home bleachers are big, though I'm guessing there will be some Padua overflow there since I agree they will bring more fans than what the visitor's side holds.
I'll also point out in case anybody who parks off of Ridge Road between the middle school and high schools, the first entrance you'll get to is the back one and you have to go up a pretty steep set of stairs to reach it. But for those who are elderly or disabled, there is the front entrance that can be reached by continuing up the parking lot road to the main entrance off of Royalton Road.
For Mansfield fans, while Cloverleaf would have been the direct midpoint, Brunswick isn't a bad consolation. It's about 15 minutes further up 71 and the stadium is less than a mile off the highway with plenty of bars/restaurants to choose from (unlike Cloverleaf which is literally in the middle of nowhere). The stadium (like Arlin) is huge on both home and visiting sides so no need to worry about finding a good seat. Parking is also plentiful around the stadium. Traffic getting out could be a little slow getting back to Route 303 but unless the stadium is packed (which it won't be for this game), I don't see it being an issue.
Raising4Daughters mentioned that North Royalton is a big feeder city for Padua, Holy Name will also have a similar fan advantage playing at Brunswick because the city of Brunswick (and nearby Strongsville) are two of Holy Name's bigger drawing areas, so Holy Name should have a noticeable crowd advantage. Brunswick seats 10,000 so it won't even come close to being full, though.