Hi Dave,
Looks like you are a little more computer savy than most - which is great
Yes, lots of Application Data, is now stored in the hidden AppData/Local/Microsoft folder which is where it should be, rather than the registry or the older XP Application Data/Microsoft folder.
If you have the MS Win-7 Easy Transfer Wizard on your XP box, might look to see if you can "transfer" just the MS Games data or FreeCell data, since you can choose exactly what to transfer over. If so, you could move just that over by a network connection, or even a flash drive. Also since the FreeCellSettings.xml is just an xml file, you might bring it up in the xml editor (view source of IE) to see the file, or any HTML editor to see if you can pick out the correct "name = value" item to modify
Lastly, might post the request over in MicroSofts Games forum which might get you a faster answer than in a hardware forum.