Take route 23 north out of Eureka Springs, AR across the Missouri Board where you'll come into Eagle Rock. Missouri route 86 from there up towards Cassville.
This is Ozark country, lots of trees, rolling hills and banked turns. I think I passed fewer than 10 cars on the stretch in mid October (admittedly a slow time) Beautiful foliage and heavily wooded.
I rode this on a return trip from Arkansas' Dragon back towards Kansas City. It is a wonderful twisty, banked, scenic blast of fun. I think I enjoyed this section of road just as much as the Pig Trail and the Arkansas Dragon that I rode the day before.
I almost called this a five, but there were a few areas of broken pavement. In all though, there were no concerns, and no or few tar snakes that I can recall.
Eagle rock has a gas station and snacks. Eureka Springs to the south has everything as does Cassville, MO to the north. Eureka Springs, Arkansas is a well known biker destination with great bars, restaurants and hotel/motels.
Motorcycle Road Additional info
I've written about the Missouri stretch, and from Eagle Rock to the route 76 intersection is best - but the entire ride from Eureka Springs to route 76 is less than 30 miles and all of it is a gas. Ride the whole stretch