That hike at Clingman's Dome is definitely steep and were it not for the benches spaced fairly close together, I'd never have made it to the top. Take a lot of breaks and you can do it, just be patient. It's actually an enjoyable climb. I'm 73 now but made that climb when I was 69. I hike a lot in a park near home that is pretty hilly, carry a pack when I'm hiking and try to work up to trips where I may want to hike someplace a bit difficult.