You're not the only one taking up that project! Prepare to spend a lot of time on the phone getting updates, if the person at the other end feels like giving you an update!
I've been doing a Pinball Maps and Driving Directions web app for the last ten years. Only in the last two has it seen any serious use.
I have a good deal of Seattle/Tacoma covered here, and a few other areas:
http://www.laughingotter.com/pinball/
Now I'm dealing with the problem of what to do when a location has more than 30 pins...