It's good to know who's responsible for what on tandem trips so the last person doesn't get stuck with anything extra.

Like Joe, I proudly triple when solo. I got into the habit with a heavier canoe and have yet discovered a reason to change style/everything to double. Three ~33# carries beats two ~50# ones in my book. Two would probably be faster but I've tried timing myself many times. I always forget to look at the end or forgot what time I started so I figure it's not very important to me. The one thing I don't do is sit at one end or the other waiting for a second wind 'cause I don't need to.

In no particular order:
1- Canoe. Paddle in hand. PFD clipped around seat.
2- Water bottle goes in the day food pack which simply gets tossed on top of the food pack. Spare paddle in hand.
3- Jacket, maps, lures are in the day pack that's tossed on top of the gear pack after the tripod is strapped on top. Camera case in hand.

Things change a bit as the foodpack lightens but it's just me. Things like rainfly, hatchet find there way into the food pack plus some gas comes out of the gear pack as the trip goes on. I could probably do two trips near the end but it would be awkward.

Like Marten said about paddles, they come in handy. It's not like I use mine as walking sticks all the time but they do come in handy once in a while.

Mosquitoes aren't a bother if you can move quickly. I've not "deeted up" for a portage in years nor do I dread them like I use to plus there's less risk of serious injury.  It's just 5 nice walks in the woods. ;)

I will sometimes have a powerbar 10 - 15 minutes before before a long portage. They always seemed to help a bit on tandem trips..