This year I was able to ride weeks 3,5,6,7,8, and 9 of the Low-Key Hillclimbs(I coordinated weeks 1-2 and week 4 was canceled due to concerns over rain).
I also started a new job the Monday following the week 3 climb, which reduced my training to essentially the Low-Key Hillclimbs only (I also got in 2 long Sunday rides and one 45-mile commute to work during this period). Previous to this, I'd had a week's vacation in Italy with lots of riding embedded within a longer period where I had weekend rides and weekday training sessions.
My scores clearly suffered from the neglect as the series progressed. I did a regression of the scores, which are normalized to the median rider (sex-adjusted) time which scores 100. Here's the result:
Curiously the time constant came out within 1% of the 42-day CTL time constant.
Anyway, not much significance here, and more sources of variability than I can count, but I thought it was amusing. It appears the 42 day time constant does a fairly good job at matching the rate at which I lose fitness. Note this is my trajectory fitness under my current level of "training": a hard hillclimb effort one day a week, four weeks out of five, with the occasional long ride.
Also on the plot I show an asymptotic projection to my week 3 result with the same time constant. I'd need to start training at the level I was pre-new-job to follow this trajectory. Not enough time before the 1 Jan San Bruno Hillclimb, even were I to get in those mid-week training rides again. And that would be hard to pull-off.