I had a spell of riding fixed, about 25 years ago, biggest mileage was 140 around Essex & Herts, 63" gear.
Normal riding was on the North Downs & the Weald, usually about 80 miles. Most riders of fixed only ever toured with a saddlebag.
I changed to riding a freewheel as my knee started to hurt going downhill, (shorter right leg), using about a 60" gear.
You do miss gears at times, obviously, but simplicity has its own benefits.
One thing I would advise is to have spare chain links & a rivetter in your touring kit.