Southern National is a .450 mile banked asphalt oval that is what most short tracks are in reality - a bullring. The driving line here is almost circular with short straights and long corners.
Traffic can be a real problem as well since there is only one fast line around the race track - the bottom. If you get high in the corners, the track tends to flatten out so you have to hit the brakes hard up there. Also, the corners are poorly marked (unpurpose) and very wide. There is a point at the bottom of the track that gets flat as well. And you don't have the advantage of a painted line to tell you where it is. But, if you follow the white line in and out of the turns you should be fine. My best advice is to follow some cars around the track so you can figure out where the line is going to be.
Pitting provides a problem very unique to Southern National. The exit-entry lanes for the pits are partially obscured by a retaining wall. So you have to be careful about slowing down too much too early going into the corners when you need to pit. Also the ai cars are going to come right up into the racing groove at the start of the corners. Just like a real short track so be careful and keep and eye open (if you can see through concrete).
Another problem you will find early on are the ai. They race you door handle to door handle at Southern National so you have absolutely no margin for error. When I first started taking laps to test the new ai at the track I was ready to thow the entire project in the trash can. I couldn't get but a few laps in without wrecking alot of expensive race cars. Now the thrill of running door handle too door handle with 20 other screaming maniacs keeps me coming back to Southern for race after race.
All in all, Southern National may be the most realistic short track made to date. It is unique in every respect and provides a real driving challenge. I hope you enjoy it.