Save this to a batch file and use it to logout of an RDP session over hamachi. Hamachi will then stay connected and online for free networks.
# This script locks the server, disconnects you from the servers RDP session
# sending the session back to console so hamachi does not get disconnected
tscon 0 /dest:console
tscon 1 /dest:console
tscon 2 /dest:console
Rundll32.exe User32.dll,LockWorkStation