Cannot connect to network drive through VPN

There are two kinds of vpn routers. One that has a vpn client which authenicates to the vpn router and one that is vpn passthrough which means you need a vpn server on the other side.

Which are you doing?

When you do the vpn do you get a office ip address?

When you say you are accessing via network drive do you mean drive letter?
Have you tried \\nasname\sharename?

Great so you are getting a local to the lan ip address.

Usually a mapping is in the form \\ipaddress\sharename

if you know the administrator account password you could do \\ipaddress\c$ which is the admin share

if you have issues with that first start with ping 192.168.0.2 when you are vpned in