Larry H. - Atlanta, GA , Aug 19, 1998; 10:15 p.m.
Try DeSoto State Park and the Little River Canyon about 90 mile NE of Birmingham on I-59 near Mentone, AL. You will also be near Russel Cave Nat'l Mon. (AL), Sequoyah Caverns (AL) and Cloudland Canyon SP (GA) and, of course, Rock City (OK, not exactly 'nature', but when I was a kid, the pollution would occasionally abate enough to really see seven states). All of these are part of Lookout Mountain, a rather distinctive plateau running over 100 miles through three states.
If you are there again in the winter, Lake Guntersville SP (AL) nearby is the wintering ground for up to 50 nesting pairs of Bald Eagles. Non-nature attractions nearby are Chicamauga-Chattanooga Nat'l Military Park, the Chattanooga Aquarium (freshwater exhibits from around the world as well as the Tennessee River Basin), and, of course, the Chattanooga Choo-Choo.
I'd try to get a room at DeSoto SP over the weekend and use that as a base. Then hit the Little River Canyon and Cloudland Canyon first. Good Luck.