Interesting observations, Marni.
I've never done a tour longer than 8 days. I found that as the days went on, I was very happy to be done, it all seemed like a dream, and I couldn't believe that I had ridden that much or climbed the mountains I climbed. Of course, any tours I've done didn't approach the amount of riding you did! When touring in Europe, and even Canada, we always take 2-3 days of plain old vacation and total relaxation before heading home. This seems to help. Of course, I never have any issues getting back into my routine, as I am pretty much a creature of habit and up until 8-9 years ago, I rarely traveled anywhere far.