Group Policy Item-Level Targeting

The DC authentication happens to give the access to the resource which occurs through SRV records in dns.

Authentication doesn't work like you are expecting,once user is authenticated user can access resource in the domain & if the only dc in the site is down, it will reestablish the same session, so there will be no way what user was accessing preiously will be lost & new drives or something will be mapped.

Drive mapping GPO can be applied at user, computer,site level or domain level,if there is no dc available user can still work bt they will not be able to access resource or update the changes.

I don't think it is possible to achieve what you are expecting.

Well. if for example the local dc went down- workstation authenticates with off-site dc controller (like it does) and if manually added the offsite mapped drives it would work. Why then can I not have a group policy or logon script recognize hey I am not connected with houston on xxxxx subnet i am connected with new york on xxxxx subnet - use off-site mapped drives instead of local. I have even considered tricking dns to map a general name like "drives" to the server ip address. for example if i have a dns order 1,2,3.. if local resources went down (1) it would hit first off-site to authenticate (2) and in the group policy programming or script programming it would try to find drives.domain.local- and it would auto map those drives. Let me know what anyone thinks.. i really want this disaster recovery

(All sites have WAFS, WAN replicated data and same folder names. Any changes on one site are replicated to the other in a matter of moments)

What about using DFS?
http://en.wikipedia.org/wiki/Distributed_File_System_(Microsoft)

"DFS provides location transparency and redundancy to improve data availability in the face of failure or heavy load by allowing shares in multiple different locations to be logically grouped under one folder"

IT sounds- in theory what I am looking for.. though I do not need actual file replication- I need more details on this feature. I need the logical file share they are talking about.