The best way to connect Crystal to ERP without BW is Crystal Reports 2013 - that connects directly to ERP tables, InfoSets, and ABAP functions.
See BusinessObjects and SAP Part I
Which enhancement package are you on? Starting with ehp5 there is a BW client inside your ERP - see What are Transient Providers? See if you have BW inside your ERP System
I am not familiar with the Rapid Deployment solutions - lately they seem to focus on HANA Live scenarios
In terms of installing connecting the best content is here by Raf Raf Boudewijns