Dear Sir/Madam, if you are interested in inventory management, you may want to search main trunk for The_Bob's commits as he made some fixes to inventory system.
I don't think you need any other debugging software apart from VS debugger which works well.
As far as I remember, debug logging goes to debug window in VS, but you need to enable various levels of debug info by using defines in the code and registering debug topics.
I don't think there's any introduction or code description, in general, if you are interested in inventory management, you just open Tactical folder and search for keywords you are interested in, and then start digging into the code. You probably need items.cpp file and all files containing "inventory" in them (look at those commits by The_Bob and see what files he changed).