SAP Best practices documents helped me a lot:
C71_CRM702_BB_CRM Connectivity ( if you need to configure the communication between two CRM using Bdocs, here is a integration between ERP and CRM, but steps should be very similar)
B09_CRM702_BB_CRM Customizing Replication
C03_CRM702_BB_CRM Master Data Replication
Helpful post/blogs
http://scn.sap.com/message/784335
http://scn.sap.com/thread/1935967
If I'm not wrong, We did the data transfer using XIF, not sure about the rest, but my part was via XIF.