OK, got it working. WOW, that was a TON of work (I had never used SysPrep) and I learned a lot, but wow.
THANK YOU for making this info available. Great to have Public now also on D:, one of the...

I choose "ISO File" in Media Creation Tool, but I keep ending up with an "install.esd" file in my Sources folder, and not an install.wim.
Even when I burned a DVD as the last step, its still a...