I ue to be a network manager in a school about 3 yrs back so heres the low down on RD and VNC:

Internally many of these ports will be allowed. But unless the school fills in a chnage control form then externall BESS or SWGFL will not allow anything other than FTP 21 HTTP 80,8080. Even if they open 3398 for RD / term services of the VNC port(s) it will be restricted to one or several interanl ip addresses. If the school has a sensibile IT policy then these will no not accessable to you!

VNC does work if if you configure ans use it properly, i have a win2k srv box with a fixed ip @ home and i rin VNC on this works a treat, i also run terminal serivces over 3398 which works fine.