Solo is tough to one pass. Some might but not me. The only way one pass ever sounded feasible to me was 3 in a tandem. But I'd hate to travel that way in a canoe. Over the course of your day you'll travel farther and enjoy yourself more by just backing down your pace a tick.

If you have a GPS, try paddling at what you think a fast pace is. Note the speed. Then try a very relaxed paddle, but keep it moving. Note your speed. You'll probably find you're only going 5 minutes slower per hour for the same distance. Not enough difference and the overall effect on how you feel at the end of the day and the next is huge. That's my feelings about portage style too. But to each their own.

If you have a small barrel too. Carry it with your canoe and keep the large barrel for gear and carry it separate. Then go ahead and bring some luxuries, but not too many either.