I tend to not stay in very good cycling shape over the winter. I always say that's going to change, but that's another matter... Anyway, I pretty much subscribe to the 10% or so increase a week once I get riding again come Spring time. My fitness base starts out pretty pathetically, but you'd be surprised at how fast you can get in good enough cycling shape to participate in a tour like the MS ride.

I try to do weekday rides either before or after work depending on how my schedule is that week. I do live in a somewhat hilly area, so I'm blessed in that regard. i.e., I get built-in interval training whether I want it or not. That probably helps my fitness return relatively quickly.

Totally unscientific, but there you go. I would never be able to follow some sort of regimented training program.