I am not 50 (only 45) and last year I was busy over analyzing all of my options on a 23 mile one way commute...

I took the bike to work and did a couple 4-7 mile rides at lunch a couple times. The next week
I found a spot about half way and rode in two days a week for awhile and worked out what I needed and didn't need in the pack. I then drove to the bottom of my hill and rode the last 18 miles to work. Later in the summer I got too lazy to load up the bike into my truck and just rode the whole way.

Each time I increased the miles it took a couple days to have my body adjust. My goal for this year is to be able to go on consecutive days and figure out how to haul the zillion pound laptop to/from work.