I've just been checking my rides from last year and adding up the total mileage (all my rides are logged on my Polar personal trainer account, I don't track every single ride I do with GPS, but do record my heart rate over every ride).
Conclusion: It's not as far as I thought it would be.
Looking back, the longer duration rides are generally quite tough and technical (The 6 Lakes passes springs to mind), rather than grinding out the miles. Also, my commute is a 14 mile round trip three days a week. I play football the other two.
I'm going to try to improve on that this year and aim to cover 2000 miles on two wheels. It's not that much further, it's an improvement.
There could be complications in that plan as I've just been entering into the ballot for the Bupa Great North Run. I'll find out week commencing 4th February whether I've been successful. Fingers crossed I'll be lucky again. Last year was my first application and I got a place, only to have to cancel due to a friends stag party.