Server 2008 - Creating a second Remote Windows Domain Controller

Hi,

We currently have a new office that's approximately 2 hours away connect with a 5 mbps vpn connection. There are about 50 users in the main office and about 20 users in the remote office.

I need to install a remote domain controller.

The plan is:

1) Create the Secondary site in AD Sites and Services window and created the new subnet also.

Is it better to also create a subdomain for the remote location or just keep the main DC name?

If someone could show me a sample plan with 5-10 steps that I could see as a guidance that would be great too.

Thanks,