I wouldn't say I'm a very experienced solo tripper. I've done two, both week long trips and in a kayak. But...on my trips I found myself lounging around in camp more often than when accompanied. Two items that make that camp time more relaxing and enjoyable for me, perhaps because of my declining youth, are a camp chair and a hammock. Both the chair and hammock I bring are small and light, an Alite Mayfly folding chair and a cheap nylon hammock I bought for $20 at Meijer.

spare paddle and pfd are essential; don't forget a watch if you need to meet someone at a specific time at the takeout, and money for a shuttle if you use a service; small shovel for latrine; anything that is mission critical should have a backup, like two lighters, or two boxes of matches - there is no buddy to hand you theirs if you lose yours - I always keep a compass and matches in my shirt pocket - in case I walked away from camp and got disoriented, at least I could find my way back to the river.

trash bag lined dry bags - your sleeping bag should have at least 3 layers of protection; pretty much the same for everything that won't stand being wet, like your food (I found a small hole in the bottom of my drybag which explains why stuff inside got wet this past weekend - multiple layers kept the bag and gear dry - lots of water in the bottom of the boat from class III rapids) a bailer is useful.

painter lines on bow and stern - anyone can get careless and flip a canoe - with the lines in place, you grab one and swim to shore while towing your boat

I always lash down my gear on river trips - aside from not losing things, it provides extra floatation - unless you already have a system in place, look at your boat and figure out how to lash the gear in before you leave for the river

I'd add a book to the list, and or fishing gear so you don't have too much down time

the usual stuff like a first aid kit, repair kit, spare glasses if you wear glasses or contacts, bug dope, sunscreen

unless you are really into cooking and then cleaning up, go with freeze dried meals

make your own list, and check off the items as you pack them so nothing is forgotten.  make sub-categories like sleeping (e. g. bag and pad and repair kit for pad);  cooking (stove, fuel, cookpot, spoon, etc - add a few paper towels for cleanup)
water (filter or iodine tablets or bleach, water jug for camp, water bottles; tenting/camping (tent, ground sheet, rain tarp, saw for firewood, chair if you want one - minimalist is a gardener's kneeling pad,

I agree with light. Also easier to stand yourself in dirty clothes than for others do I have a spare in case I get wet but not much more. One pot and stove. Otherwise just light weight.  I'm not a rain suit person - never carried one and never missed it. I do have a light rain coat with hood, but I'm fine with quick dry pants and avoiding getting dry pair wet.

End of day, you need two packs or able to divide weight for balance.

I do envy those that solo and single portage, but not enough to do it.

And books. Mystery, spy, and summer fare. That's my fun in the sun on the shore all alone.

My advice would be layout what you think you need in piles from left to right on the floor. To the right of that, put what might make you the happiest in logical piles from left to right.

Then lay out the containers you are planning to take and take everything that fits. Then look at what's still on the floor and consider it's possible usefulness durning the week.

Too much food has always been one of my problems since the trip we paddled the last long day with nothing but peanut butter and Tang for fuel. When you return with clothes you didn't wear that means you had a good weather trip. The way I look at it the more I take, the more exercise I get.

A positive attitude is, as you probably know, the smallest, lightest and most useful thing to bring along on any trip and you can't borrow one on a solo.

ENJOY!

Bringing the positive attitude is one thing, keeping it when things get tough is something else.