I've finally noodled with OpenVPN enough to get it working. Even better, I can mount samba drives, ping network machines through the TUN device, etc - it's all great.
However, I'm noticing that if I use the following directive, then some of the machines that are normally visible by the client, on the client's side (i.e., not through the VPN) get masked with some other server out on the Internet.
push "dhcp-option DNS 10.0.1.1" # Push our local DNS to clients
Is there any way to avoid this, besides hacking the 'hosts' file on the client machine? Ideally I'd like to only use my VPN's DNS for machines within that domain.