You can get a track map at:
http://www.beaverun.com/This is my home track and I have to believe that I am closing in on 1,000 laps around there. I am a track instructor for the facility and often get calls from the management when they need additional instructors for the marque-based events. This year has been hard because of some health problems with my wife. Regardless, my dad instructs at almost every track event and he will likely be there for the BMW event.
As far as the track is concerned, here are the things to consider:
The braking zone into Turn 1 takes a little time to get right for a specific car. Initially, the braking zone is uphill. It then crests and goes downhill. As you move your braking zone forward, all at once, braking effectiveness is greatly reduced since the road starts falling away from you. Start at the 200ft marker and move up as you gain confidence.
Turn 7 is a blind, off camber, downhill, right-hander. After a couple of laps, you will end up picking a tree out on the horizon to use for your turn-in point since you can't see the apex. Cars with good grip and medium to low power can take this flatfooted. My car MIGHT be able to take this turn flat-footed, but I haven't gained the courage to do this yet. I plan to do some testing later this year and try.
Turn 9 is really a kink on the backstraight. Like turn 7, many cars can take this flat-out. I tap the brakes in a straight line there (I'm in 5th gear) then floor it using all of the track and start braking for 10 as soon as the car is heading straight. DO NOT LIFT GOING INTO THE KINK. I have seen literally scores of cars destroyed at this turn. The driver first chooses to take it flat-footed then changes his mind after initial turn-in. The lift rotates the car and you will end up hitting the Armco with the passenger side. Creep up on speed through this turn slowly.
Turn 10 is a sharp, uphill right-hander. I have tried many lines through here and for my current configuration (low power), I found that taking the turn in the middle and tracking out to the outer curbing helps me carry more speed up the hill and onto the front-straight. A higher hp car might benefit from a tighter (and thus shorter) line but it's down to the car.
Everything else is pretty straight-forward.
Beaver Run is extremely hard on brakes. In fact, I have driven about 10 tracks and this is by far the hardest on the brakes. Make sure that your pads have lots of life left and make sure that your brake fluid is fresh.
When are you going?