If you're technically minded, you could simply run a batch file that uses robocopy with the /MIR switch whenever you needed to synchronise your laptop back to the NAS. http://ss64.com/nt/robocopy.html
robocopy is available natively in Win7.
I also use the free GUI based SyncBack on some machines: http://www.2brightsparks.com/freeware/freeware-hub.html
You can create a job and just run the job whenever you need to.
You could schedule both of these to run at logon too...