Commuting helps a lot. On a good year I commute to work 4 times a month..that is 200 miles a month in and of itself. That is 2,400 miles annually.. Some years I commute on average, more than that.
My log said during 2002 I had 3 months with over 1,000 miles. Then each of the last 3 years I have had a bike tour.
My tours have been from about 400 to 900 miles.
Getting that kind of mileage is not that difficult if you commute and ride with a club... One member of my club suspects he has ridden over one million miles?? He is working on a 300 mile day? I work compressed days and have off more days per week than most.. When I am at home and my wife at work, I ride, ride , ride. She wishes I would do more yard work...