I'm thinking about a similar problem, but perhaps more daunting. I have a program which is my first real app. I work alone, it's over 40,000 lines (that includes comments though). Part was written before I knew very much about coding, and it's very tempting to try to make it all neat. (I have nested inner-class messes that are pretty hilarious).

It seems unit testing would be key, but it's problematic in that everything is private! Getting the bird's-eye view is an intriguing thought, but I'm wonder how to actually go about the refactoring itself?

I could avoid it, but it seems that I'm already hacking code that itself was a hack (cuz I didn't know what I was doing). It makes updating and extending a very time-consuming proposition.