So this is what I'm dealing with (clicky for biggie). 67 stations on the blue (Northern) and green (Wirral) lines. It doesn't sound much, I know, in comparison with the hundreds of Tube stations, but there are a couple of key differences which make this an onerous task.
1) Lack of interchanges. There are only two places where the Northern Line meets the Wirral, and they're both in Liverpool city centre. After that, they branch off all over the place. There's no option of taking a Bakerloo train or a Jubilee to get to your destination; once you're on a route, you're stuck!
2) Service frequency. Only in Liverpool-Hamilton Square is there Tube-like frequency; everywhere else it's a fifteen minute service (except at the outer edges of the Wirral line, where it's every thirty minutes!) So if I hop off a train, I've got to loiter for a fair while for the next one. Not a particularly pleasing prospect in such well know scally-heavens as Kirkby and Bootle.
3) I'm on my own. For the moment, anyway. Right now I'm keeping this a private project, between me and, yes, potentially billions of internet readers, but that's not the point. I haven't told any friends or loved ones yet. Let's get the project going first so there's something worth seeing!