After CMS Data Challenge (DC04)—which was devised to test several key aspects of the CMS computing model—a deeper insight was achieved in most crucial issues for a successful Tier-1 operation with real data within the overall CMS computing infrastructure. In particular, at the Italian Tier-1 centre located at CNAF, several improvements were implemented in one year since DC04, concerning the data management, the data distribution system using the CMS PhEDEx tool, the coexistence of local traditional farm operations and Grid official CMS Monte Carlo production, the development and use of tools to grant efficient data access to distributed users to analyze CMS data via Grid tools, the long-term local archiving and custodial responsibility (e.g. MSS with Castor back-end), the daily CMS operations on Tier-1 resources which are shared among LHC (and not only) experiments, and so on. The outcome of CMS DC04, as well as the CMS use of INFN-CNAF Tier-1 resources, are briefly reviewed and discussed, yielding indications for a roadmap towards the operation of the regional centre when real data from LHC will be available.