Here are TRIMPexp scores for a few different activities (ELT=elliptical trainer, EXB=exercise bike, SKI=skiing, SWM=lap swimming, WLK=hiking), plotted by duration.
Elliptical trainer or exercise bike sessions would have been ideal for comparing the effects of different routines on recovery as they can be done regularly, and in a more or less controlled environment.
Unfortunately, activities with a score of less than 500 don't seem to have a measurable impact on the next day's HRV, which is how I was going to measure recovery. Activities with a score above 100 may have a cumulative effect if done daily (not happening), and activities with a score of 500+ are infrequent (once or twice a month), and not very controlled (i.e. I'm not repeating the exact same hike multiple times under similar conditions).
Nevertheless, I'll keep tracking heart rate while hiking, as well as doing daily HRV measurements throughout this summer