Adding a second domain controller at a satellite location

I'd like to add a second domain controller at a satellite office as a preventative measure for a disaster scenario.  I'm running Windows Server 2008 Standard and the satellite office is connected to the main location via a VPN appliance.  

I have two questions.  Are there any problems with adding a server as a domain controller while it is in the satellite office.  My concern is transferring all the data necessary to make the server a domain controller via VPN.  Should I set it up in the main office first and then move it to the satellite office?  

My second question concerns maintaining a domain controller in a satellite office connected with a VPN.  I wouldn't think there would that much information transferred between the two servers to keep everything up to date.  My concern here is regarding bandwidth.  Does anyone have experience with maintaining a second domain controller as described?

Thanks.