I wrote about marking and exchanging point and mark without activating TMM:
https://www.masteringemacs.org/article/fixing-mark-commands-...
Also, the CUA rectangle stuff's actually mainlined and can be used without CUA (`C-x SPC')
I didn't know about C-x SPC, thanks for the tip!
I enjoyed your article but I think the solution for me is to leave TMM disabled, though it makes me curious about what else I've missed in the last decade(s). You just made a sale of your book.
I'm one of those weirdos that disable transient-mark-mode because I don't feel like it does the right thing for all situations where you use mark. Sometimes I want to use mark like a cheap bookmark and C-x C-x between mark and point, sometimes I use the rectangle commands and for those transient-mark-mode only makes things worse.
(I know the CUA mode has some fancy rectangle features, but that's not for me)