Ok, so I'll bite on this one.
I too am floundering as I make the transition from outside to inside.
I have figured out a way to do a quick stint at the gym for an hour in the morning - I race-walk at lunchtime.
It's dark when I leave work for the day so the weekends are when I can cycle for any length of time or distance.

Any advice on how to keep my hard-earned century legs over the wintertime is much appreciated.