I'm just finishing week 3, I'm going to take a week off and then start Art of Waterbury. I plan to use the downtime next week to play with the poundages so I can figure out what weights I'll use for AofW. I guess I'll get mini-workouts doing this, but nothing intense. I've taken a week off before, and mentally it just makes me hungry to attack the next program when it starts.
If you really want to keep going, I'd do the 4th week and then take a week off for sure. There is rhyme and reason to CWs ways.