The Pig Trail in Arkansas and then on to the Oark General Store.
I'll second Arkansas as having lots of fun roads. I can't remember all the details, but about 40 years ago I went on a great drive with the BMW Club through the heart of Arkansas. We started at Mt. Ida where we pigged out on pies at the famous Mt. Ida Cafe. Then we took various scenic, curvy roads until we got to the beautiful Magazine Mountain overlook. From there, we made our way west and north to Eureka Springs. Though we were driving our four-wheel Bimmers, I would imagine that riding two-wheel Beemers along that same route would be just as much fun. Maybe Faulkner, our resident Arkansas guru, could add some suggestions.