Greg, this is a good description, except for one little error. South Cobb Drive is State Road 280. Further east is Atlanta Road, State Road 3, and then, several miles further east at this point, is US 41, or Cobb Parkway. A lot of people are confused by the similar names.
Ruff's Mill was near the Concord Covered Bridge across Nickajack Creek. The area is now a historic District, so the surroundings are not too different from the war years. The bridge was burned, but rebuilt in 1871. Historical markers are located at this site: http://georgiainfo.galileo.usg.edu/gahistmarkers/battleruffsmillhistmarker.htm
You can see Kennesaw Mountain from Concord Rd. and South Cobb Drive. I live about three miles from the intersection, north of Windy Hill Rd., and was born in Marietta, near the National Cemetery. Back in the day, the road up the mountain was gravel. We would ride our bikes to the top and coast down. It was consideered "chicken" to use your brakes! It's a wonder some of us weren't killed! The view from there is great, as well.
Col. Solon Z. Ruff was the second in command of the 18th Ga., and later CO, after Wofford was promoted at Fredericksburg. Ruff had been a professor at Marietta Military Academy, where the Marietta Civic Center is now located. He was killed at Knoxville, where Captain James Lemon of Co. A was captured. Captain Lemon signed my great uncle Alex's pension application. Uncle Alex was captured at Cedar Creek October 19, 1864. They were POWs togeter, at Point Lookout. Stan