I find it's trickier to do all this solo than tandem, as I prefer to single portage everything (in one big bag) and it helps to balance things when you have a couple bags... the up side is that you are in the middle, or just aft of the middle, and can pull or push that single bag in front of you so that it balances. I've used logs and rocks too, when it was windy and I needed to add weight to the back, but murphy being what he is, I seldom get a blessed tail wind.
For most my tandem trips, it's me and my daughter. we carry two backpacks and a food bag/bucket/box depending on trip length. the two packs go in the middle somewhere, and the food goes ahead of that somewhere to balance it.
If you use the same canoe for most trips, it gets easier w/experience.