Hi bobverheul,
Unfortunately there is no direct way to move Fonts folder from its default location to somewhere else, instead you can move unnecessary fonts from fonts folder to another drive. Then install the moved fonts as shortcuts. This would not only give you decent amount of space in your C: drive but also consume less space as well.
In order to do this, you can open the Fonts folder either from the Control Panel or by going to C:\Windows\Fonts. In the Fonts folder you need to click the Font settings option from the left pane, and then you need to check 'Allow fonts to be installed using a shortcut (advanced)' checkbox under Installation settings section.
Once you click OK, right-click the desired font that you want to install and that might be placed at any different location other than the default Fonts folder. You can then click Install as shortcut option and follow on-screen instructions to install the selected font as the shortcut.
Don't forget to log on using administrator account before performing the above tasks, or you might be asked for administrator's username and password when you try to follow the steps.
Hope that helps.