Is there any one open source software package that can perform both road network analysis and geocoding?
There is or rather, there was. PostLBS is a project which aims to provide core tools for Location Based Services (LBS) as Open Source Software (OSS) that can provide Routing (pgRouting) and Geocoding (geocoder.ja. Currently for Japan only) functionalities which are similar to those found on commercial software. Unfortunately, it seems to be gone now.