Thank you everyone.
@TB, Part-2 will touch on this, but I would consider creating the CAS Array Object with a friendly FQDN name (e.g. 'outlook.domain.com') , create an A record with a low TTL value (5 mins maybe), set RpcClientAccessServer to point to that FQDN on all DBs, and temporarily point that DNS record to one server for now. It'll mean manual failover for now by changing the DNS record (why we want the low TTL), or if both servers are on the same subnet you may be able to get away with adding an IP to one box, point the A record at that IP, and then move the IP between servers when you have to. If you never plan on implementing a DAG (which you should! :) ) then Windows NLB could be stop-gap option, but we generally recommend a Hardware Load Balancer for all customers. You can usually find me in the Exchange 2010 TechNet forums if you have more detailed questions, but some more coming in Part-2....