don't really know what windows would do to your files/permissions, etc.
if you have room, i would make a disc image of your drive then zip it, or just take the files of interest and zip them.
transfer them to the pc, transfer them back to the mac, unzip and try them out before wiping the mac clean
if that works, then go ahead.
file sharing to a pc is beyond me, although you should be able to scp or samba them if you know how. i would use scp (turn on remote login on the mac and use putty or a ssh/scp client on the pc) because i don't know jack about setting up samba on a pc.
also, for the really important stuff, back that up to a cd or 2 from the mac.