You're definitely putting more thought into this than most other alleycat'ers (that's a good thing). The fact that they've already published the route tho tells me its more organized than a traditional 'alleycat' or messenger race. Every one I've ever done (too many to count) is a show up, get your manifest, look at a map for 5min, choose your own route and haul butt when they say go kinda thing.
...for the wife, I stopped doing them when I hit 32. I've been hit by way too many cars on both my bicycle and my motorcycle.