Classic taper = same intensity, lower volume. I say take your recovery day and hit the hills hard Tuesday, as you normally would. After that, do everything you would normally do, but only 1/2 to 1/3 as much. So, two hill repeats instead of five or six, three 1m intervals instead of six, 25 miles of tempo instead of 50, two sprints instead of six, etc.

Enthalpic is right though, the Performace Manager in CyclingPeaks will tell you how to taper. You could take your best shot at it this week, then you'd have data to look at for your next taper.