Redirected folder syncronize

I am trying to implement folder redirection (My Document only) in a
windows 2003 and XP Pro SP2 environment using GP. The GP is working
just fine, all I am trying to figure out how and when to sync the
redirected folder. Please note all my users use laptops.

Since the content of the My document folder is very large(sevaral
GB's)I am concerned that if I enable the sync at logon or at logoff
which are the default for XP, then logon and logoff time will be
extremely long and that will not be acceptable to many of the users.

I need some help understanding how to avoid this issue and yet make
sure that when the user is off-site they have a complete cached copy
of their My document folder.

Any help is appreciated.