Excellent stuff here -
If you want to access it once every time you are logged in - hold down shift and right click (or whatever your secondary click option is) and run the AppleControlPanel.exe as a different user (standard account) and it will come up with keyboard and trackpad settings - only problem is they will disappear after a reboot.
To alleviate that, using the help above and ProcessMonitor, I was able to track down the registry keys that this affects and what settings it applies - in my case I wanted right click in the bottom-right and tap to click enabled - this is what I've come up with - Either HKCU or HKU\SID## will work for these paths - I used Current_User as I was logged in with the admin account:
\Software\Apple Inc.\TrackpadMode -
Decimal value 8 - nothing enabled
Decimal value 105 and the above two settings will be enabled after reboot, along with the default of 2-finger secondard tap
Decimal value 41 - tap to click and 2-finger secondary tap
Decimal value 43 - tap to click, 2 finger secondary tap and Dragging
Decimal value 47 - tap to click, 2 finger secondary tap, dragging and drag lock
Decimal value 111 - tap to click, 2 finger seconday tap, dragging, drag lock and seconday click bottom right (bottom left is 239)
Haven't gone through all combinations, but might build a interface if several are interested.
\Software\Apple Inc.\Apple Keyboard Support\OSXFnBehavior
Decimal Value 1 is default - fn key to get regular F1-F12
Decimal Value 0 changes to standard function keys - fn to get apple special commands
This still does not get you into the control panel, but its a tad faster than roaming between two user accounts.
Also trying to figure out why the AppleControlPanel.exe is set to Run As Admin under an admin account, but not under a standard user account - it always prompts for it under admin account, could have something to do with my group policies.
If you'd like a script or GUI to do this from (until Apple fixes this) let me know and I'll get one going.
This is all tested on a MBP Retina with Windows 8 RTM - has been an issue on all previous releases as well.