I would like to know the answer as well. I have a short canoe trip coming up on around day 27 of a 40 day round. I wanted to take a couple day interruption and eat p3 during my trip. I don't want to take 4 full days.
In your situation, I would probably do a planned interruption. I've found that both of my 'interruptions' in my second and third rounds really helped boost losses once I returned to p2 as well. Good luck reaching your goal and have fun on your trip!