Windows 2008R2 Backup Terminal Server

We want to have a DR Terminal Server in case our Primary site goes down. What is the best way to go about the CALS - we currently have the calls on the Active TS Server

Can we set up a second TS server (Different AD Site, but Same domain/Forest) and have the same CALS available to that server - 

Do we just add the second TS to the License Server - 2008R2 standad

Thanks SJ