I've got a really nice route that I did back in the fall around the Riverside/Heard's Ferry/Northside Drive area. It's got everything-big hills, little hills, no hills and I don't have to get in the car to go. The Interstate North Parkway entrance to the Chattahoochee River NRA is only a couple of miles from my house. Great, close entrance to Columns Drive (flat 2.6 mi paved road with bike lanes that parallels the river).
Great suggestions everyone--It's a sunshiny day, so I think I'll stop talking and head out. I'll let you know how it goes.

