Thanks, we appreciate the constructive input!
I can tell you right now that "Download Ubuntu Desktop ISO local" isn't required.
Install Vagrant and it's dependencies, then however you use the command line on Windows, you do the same as on OS X and Linux, you run
vagrant up from the Trellis directory, after following the same instructions for installing and setting up Trellis. You don't create a new virtual machine manually, Vagrant handles all that for you, neither do you install Python or pip manually. I don't see where you got any of those instructions from the Windows docs.