@jbjones A loooong time ago I used an Adobe Illustrator 10 upgrade package, installing it with AutoIt. The upgrade was satisfied when it found the 450KB os.dat file that I had copied from my full version of AI9 onto the CD. Here's a portion of that v2.64 script to give you an idea:
CODE
WinWaitActive, Adobe Illustrator 10 Setup, upgrade installer requires proof
Send, {down 2}
Sleep, 500
Send, {SPACE}
Sleep, 500
Send, !n
Sleep, 500
WinWaitActive, Adobe Illustrator 10 Setup, Search a specific folder
Send, {DOWN}
Sleep, 500
Send, !n
Sleep, 500
IfNotExist, C:\\Files\\setup.exe, Goto, next1
WinWaitActive, Find Product Application Folder, Select folder where the product
Send, C:\\Files\\AI9
Sleep, 500
Send, {ENTER}
GoTo, continue
next1:
IfNotExist, D:\\Files\\setup.exe, Goto, next2
WinWaitActive, Find Product Application Folder, Select folder where the product
Send, D:\\Files\\AI9
Sleep, 500
Send, {ENTER}
GoTo, continue
Etc., etc. I had it searching for the CD as far as the H: drive. Once it found the CD, then the directory path to os.dat was entered. All of this could be accomplished much more easily using AutoIt v3. If you can do it with a keystroke or mouse click, you can do it with AutoIt.