Well, you know me, I'm no expert so read at your own risk

I would say work on the riding every day (or as often as your crazy schedule allows) part first, increasing your distances as you can, and then start focusing on the century training. Those century training plans are usually designed for someone who is a reasonably strong rider already, so you might wear yourself out and get discouraged if you start on a plan too soon.

If you've got to have a plan to work with, I would sit down with some paper and draw one up. I think you're supposed to increase your mileage every week or every other week by 10% or something like that. When I was doing my walking thing, I just customized the training program I found on http://www.the3day.org (PDF) . You could always customize one of the century training plans to better fit what you're capable of riding now.

Basically, I'm giving myself this summer to get in better shape, and then I'm hoping I'll be able to do at least a metric century by the end of next summer. Our little challenge is helping quite a bit toward those goals