If you're in the southeastern Ok/southwesters AR area check out this gem of a road that runs between Talihina OK and Mena AR. It's one of those protected scenic roads just like BRP, with no gas stations or billboards, just two lanes and natural beauty. TSD is 54 miles long and winds along a high ridge, offering some really great scenic views and basically no straight and/or level parts- my kind of raod! Your Beemer will feel 'in it's element' there! One of my favourite road signs is along TSD, and says something like "Caution- road steep and curvy next 13 miles."
Fall colours are spectacular up there, at least when the road dips below the cloudline. There's a state park on the AR side which has a nice lodge you can stay in for reasonable. Very few TV channels there and your cell phone will be out of range- great for getting away from civilisation! Book way early for a room during september/October though! Much nature to explore when the weather's nice.
The AR state park is where the Chain Gang holds the JailBreak In The Clouds rally BTW (nice cozy small rally too!)