I have used hamachi in the past.
its a pretty simple vpn program and its free
install the app on the pc (you want to host resources from) then create a LAN/network name and password
install the app 2nd pc and click join - type your network name and password that you created.
next, map a drive of your shared resources (\\5.x.x.x\C$)
it uses the 5.x.x.x ip scheme to give you a temp ip address. Once your joined together in hamachi it will auto connect and show the ip of the computers on a list so you cant forget. its a pretty cool tool. hope it helps
no port forwarding
no router/firewall configs
if you want to use remote desktop you can use hamachi and realvnc combo ;)