Hello Jeremy,
Colour me interested. Not so much in Golarion, but I figure if it can be done for one setting then why not another. This doesn't so much sound like an experiment in mapping as in programming though. If you don't intend to do gradual zooming (in/out) but rather "jump" between maps of different scale (i.e. world, continent, nation, region, town, building) then other than getting a hold of the various maps/schematics the rest should just be coding.
I'm a software developer myself (web applications mostly), and have brushed up against this very goal a couple of times but in the end the effort was too daunting to tackle alone. I'd be happy to chat more about it though.
Best wishes, niekell.