w00t! Great Post!!!
Southern Missouri and Northern Arkansas have some pretty good roads to ride...
* Hwy 19-S from Cuba to Thayer (just under 150 miles).
Cuba is approx. 80 mi. southeast of downtown St. Louis off of I-44. Thayer is the southern-most town on Hwy 19 in MO. It is about 1-2 miles north of Mammoth Spring, AR. Once you're in Thayer you are basically in the sticks. Either enjoy the trip back or check out some of the roads in No. AR.
Btw, great detours exist all along the way. Particularly through parts of the Mark Twain National Forest. For example...
(1) Steelville (8mi. south of Cuba along Hwy 19) to Potosi via Hwy 8-E (35 miles).
(2) Potosi back to Cherryville (10mi. south of Steelville along Hwy 19) via county roads P, C, Y, and V; Hwy 49-N.
That detour is just under 80 miles.
* Mammoth Spring to Eureka Springs via Hwy 9-S and US 412-W/62-W (approx. 150 miles).
Fantastic detours all along the way...
(1) Mountain Home to Midway via Hwy 5-N
(2) Midway to Bull Shoals via Hwy 178-W. Bull Shoals Lake is a beautiful, deep, clear-water reservoir. Nice place to stop, stretch your legs and take in the scenery.
(3) Bull Shoals to Flippin via Hwy 178.
Flippin is back on US 412/62. Detour is approx. 35 miles.
Grab yourself a topo Atlas for Arkansas and use your imagination. The Ozark National Forest lies between US 62/412 and I-40. That sh_t don't stink if you get my drift...
(1) From Harrison head south on Hwy 7 into the Ozark National Forest.
(2) Hwy 7 to Deer to Hwy 16.
(3) West on Hwy 16 to Hwy 21.
(4) Hwy 21-N will eventually get you back to Berryville which is about 10-12 miles east of Eureka Springs.
That little detour is about 105 miles. Try not to crap yourself.
US 62/412 actually has a moderate amount of traffic. But like I said, if you have a good topo or road atlas for the entire state... you'll be able to find tons of good alternative routes. Arkansas does a nice job of keeping their roads in shape (at least the ones I've ridden). The scenery is incredible.
From Eureka Springs to Rogers on US 62 actually has some insane twisties for a 5-10 mile section... Too bad that's where the traffic really picks up. Eureka Springs is a tourist trap and the Rogers/Bentonville area is the home to Wal-Mart... so you can get an idea of with all of the cages and trucks riding their brakes.
The Best Western hotel (might be others) in Eureka Springs offers a discount on their rooms if you're on a bike.
Cheers and safe riding,