Perhaps there are parts of your question that I do not understand. In particular I am a bit puzzled at your use of the concept of AS in a discussion of OSPF. OSPF does not really process the concept of Autonomous System. From my perspective thinking about two OSPF AS would be something like running OSPF at the DR site, running an entirely different and separate OSPF at the main corporate site, and having something different, like BGP or EIGRP running in between and sharing routes from the two separate OSPF implementations. I am not sure that this is what you had in mind. Perhaps you can provide some clarification if this was not what you had in mind?
My suggestion would be to run one OSPF and perhaps to have the different sites in different areas.
HTH
Rick
HTH
Rick