Setting Up a DR site.

Hi all Gurus out there.

I have a pair of AD at my production site (same h/ware) this is access by 
user from few countries. The proposed site for DR will be link by 1 GB
line 
to production site. The h/ware used at DR is using different h/ware.

I would like the DR site comes to live when production site goes totally 
unavailable.

Question are:-

1. To setup a single domain with single site or different site for my dr
plan?
2. To setup new domain (new tree)  under same forest for my dr plan?
3. How Can i copy existing user account and security policy to my new
domain 
   (DR site) for easy installation.

Thanks in advance

Rick