A few months past mile marker 54, 6'1", 235-240. Car-free commuter, ride a MTB (my low back/joints won't take a rigid frame, tried...); my personal best for mileage is 52 on a 'joyride' a little less than 2 years ago. I have multiple commute routes, HATE getting 'in a rut'; they range from 2 to 9 miles each way, and I can mix/match as I choose. Anything up to just over 5 miles, I can average 15mph. Over 10 miles, that drops to about 11.
Everybody carries a self-image in their heads; mine is, one way or another, connected to/with a bike....