It works!
Well, almost. If you have, say, notepad open and in focus on the remote system, when you hit Q, a Q will be typed into the document. But holding Q down and continuing to hit Alt + Tab WILL then proceed to cycle the
local windows. Cool.
But having the Q be typed remotely is not ideal. So you first have to make sure the program that's in focus remotely does not respond to Q. So it's still a two step process. So, again, i think some special key to switch focus back to local windows (which is also an extra step) is cleaner, and an acceptable lack of convenience.
Windows doesn't have a special notion for "remote" and "local" windows, hence we need to invite ways to split the Alt + Tab behavior for these two categories.
This a bit beyond me, but, if I speculate, most programs do not process, themselves, Alt + Tab. Rather Windows catches that and cycles thru windows. So I am guessing that RUT has some way of intercepting that, and directing it to remote windows instead. So what I suspect would work is that, say, Shift + F12 would turn off that feature of RUT capturing Alt + Tab, and then let Windows capture it and do its regular cycle. And then we'd need a way of setting it back so Alt + Tab goes remote again. In my opinion, when the local window (which contains all the remote windows) comes back into focus, Alt + Tab should automatically shift back to remote. Another way of saying this is that Shift + F12 only temporarily lets the local windows see Alt + Tab. This is awfully technical for a speculation ;)
That documentation you mention sounds very useful!