Isn't that typically what the briefcase feature was for?
Having both a remote and local copy of files that could be synchronized?
Why redo network features when something like that would be infinitely easier?
Rather than storing files in my documents, which are
as you said
transferred at every logon, it is a better option to store them in a mapped
network drive that reconnects at every logon... a different one for every
user that connects as U. That way the my documents directory gets
transmitted very fast... but the network drive is not transferred.