I would imagine that you would need to put the entire Classic folder on the disk for it to work properly (as opposed to just the Interface and WTF folders) but as I understand it, it should just be a simple cut and paste to move the folder once it is installed. You would just need to do that every time you rebooted the machine before you tried to play in order to see the benefits of it.
as far as software, really once setup they all do the same thing and there are tons of free RAMdisk programs out there you can use, I know AMD makes “Radeon RAMdisk” and is one that is free you can download, but there are many others that are great programs you can use.
edit: I agree with Amris and Williams, just use a good SSD and call it a day.