It wont appear in the network neighbourhood. Netbios traffic shouldnt broadcast outside its own subnet (not too sure but i think it is blocked at the firewall any way).
I wouldnt be too keen about allowing the 98 machine any access into the lan anyway as you are running an inherrently insecure operating system as your gateway. If it gets hacked and you have open paths in to the lan, they will soon follow.
But to answer your question, you should be able to vpn into the system and treat the gateway machine as an local machine (I think).
Regards Duncan