The Draytek Vigor is a good router. On the surface they look overpriced (eBay is your friend) but they use the Windows VPN client and are a doddle to setup. I still prefer the Sonicwall TZ170 personally.

Rather than shifting .mdb data across the wire, personally I would simply use Server 2003's remote desktop connection and merely use the travelling PC as a terminal. AFAIK, you get a bundled 1-user administrator licence for remote desktop. The benefits are that you're reducing the risk of corrupting the .mdb file if your remote connection drops, you are not carrying possibly sensitive data around on a laptop that is easily lost/stolen, everything is taking place on the local server so your remote connection speed just limits your screen updating speed, your remote PC requirements are minimal.

As far as remote desktop goes router-wise, VPN is the more secure option. Not recommended but if you know the IP range(s) you will appear on remotely, you could take the risk and use port forwarding I suppose (choose a strong password and keep the server patched!).