Thanks to John at Res4, who helped me fix a little problem I ran into finishing the roof eave on the backside of the house yesterday. Turns out that the roof trusses on that side of the house didn't extend far enough to leave room for the air vent. So following John's suggestion (after talking to him on the new phone service installed at my house!), I extended each of the truss ends - the white of the house wrap is where the original truss ends - before fastening the 2x6:
Another roofer came out to the site yesterday; we should get an estimate from him by the end of the week and soon we should have a finished roof!