You can use GPOs to set the all those settings which will prevent them from changing them.
If the user will be saving files to the my documents folder and they want those files available on all machines you’ve got a couple of options.
1. You can use folder redirection to redirect the folders to a network share on the server.
2. You can setup roaming profiles so that every time the user logs into a workstation the files are copied from the server to the workstation.
Roaming profiles are nice because if the server isn’t available they can still access the files, all be it an older version of the files. However you will quickly start having machine running out of space as the files start to fill up the workstations C drives.