The Smokies are a great place to start. I did my first trip there (at age 42) of 100 miles over 10 days. Lots of options!

I'd encourage you to go lighter though you're clearly used to heavy loads. Perhaps the paper I wrote can assist you in that. I also did videos of all the equipment I used along with the pros and cons, etc. Those start here. Those were low resolution unfortunately as I didn't have a large flash card and they were pretty long. I also did a followup series on gear changes I'd made the following year.

The past 3 summers I've taken my sons on long road trips out west to hike/backpack and will continue to do so.