Once in the series, Dr. Kroger made up his mind to retire. That plot is
likely a foreshadowing of things to come. 'Monk' is scheduled for a
summer season--- this past year was cut short by the writer's strike,
I believe. I wonder if it's currently in production, or if they'll
have the full hiatus to figure out what to do?

The folk music connection explains Capt. Leland Stottlemeyer's
flirtation with folk music, a sometimes humorous interlude, and
perhaps his Lieutenant's 'garage band' pretense.

Monk's scenes with Dr. Kroger were key features of the plots, being
a handy way to conduct some exposition without any need to 'work it
in.' They're going to have to replace him.

I wonder if they'll kill him off in some dramatic fashion, to give
Monk a 'case' to solve. Stanley Kamel would probably enjoy that.