Thank you!

No, generally US and Canada border entries do not scrutinize the entry record to the other country beyond the few cursory questions ("how long were you in Canada, purpose of your visit, where did you stay" yada yada yada bla bla bla). The reason for this is because they are among the few countries of the world that do not have passport control at exit.
That said, the US officer could manually consult with their counterpart on the Canadian side for this but unlikely to happen for a sober, clean and simple appearing soul presenting themself for a return entry home.

#22 If the US border official scans his passport they will see the criminal record that keeps the OP out of Canada, so being 'a sober, clean and simple appearing soul' may not be much help. The OP is making a dubious assumption that sneaking across the border into Canada is only a crime in Canada, it might also be a crime in the US. For example, if a US border patrol officer finds someone in the middle of the night by a river that forms a US border, in their swimsuit with passport and clothes in Ziploc bags, obviously the officer will check the passport and if there is no evidence of US entry then arrest for illegal entry will follow, but if there is a legitimate US entry I doubt the officer is just going to wish them a pleasant swim to Canada.

True. The imagination can dream up any numbers of scenarios that would cause a border officer to pull up a history. They even have the option to contact the other side and have them look at records in the other country.
Yes, the US border office can see the US criminal record that kept them out of Canada. But on the return, the US border officer generally doesn't care about Canadian admissibility when returning from the US. Yes, the US border officer could call up Canada and inquire about how they entered and on what basis they were successful in doing so but that is highly unusual, particular for a clean shaven fellow returning HOME to the US. So, yes it does help in his specific circumstance.
The context of the question by the original poster was not in the middle of the night by a river border. It was returning back HOME to the US from Canada. And having made 100s of crossing between the two countries over the past five years (living in US, working cross border in Canada on a daily basis), I can state with confidence that only in extreme circumstances (yes, probably middle of the night by the river is one of them), it is VERY rare that a US border officer would contact his colleague in Canada and inquire about the basis for their entry into Canada, particularly when negotiating a RE-ENTRY back HOME to the US at the proper crossing.

Dude, make your way to Chicken, Alaska, then take the Top of the World hwy to Dawson City. The only border control, for lack of a better term, is for the US coming back, 1 guy and his dog at Poker Creek, not kidding.
Probably be fairly easy to hitch a ride outside of Chicken. Good camping and fishing on the Yukon River just outside Dawson.
No Canadian customs.

I'll answer my own question having done it now.
Handed my passport over.
"How long were you in Canada? Purpose of trip? Do you have any firearms? Do you have any animals? Do you have any fruits or vegetables? Do you have 10,000 in cash or more? Enjoy your stay in Alaska sir." And handed my passport back and I was on my way.
My friend did a similar thing and reported a similar outcome.

Far out!
Where did you cross the border at?
Was the " official " Canadian or a Yank.
How was the fishing?

Alcan Border/Beaver Creek. I'm assuming American. Don't think border patrol can be Canadian.
Canada was a wonderful country! Banff NP was the prettiest place I've ever seen. Did some hiking, hot springs, saw many bears, Northern Lights, and the people here are truly welcoming and generous. No fishing unfortunately, never got around to getting a pole.
It's a shame it's one of the two countries on Earth I can't (legally) enter. Along with Australia. Especially because I'm just here to enjoy it like everyone else.

Western Canada, the Yukon and Alaska have some of the most stunning/scenic country in the world, IMO. Yes, the people are very friendly. Good fishing too!
To bad it's freezing for 9 months of the year.
Don't worry to much about Australia, it's a cool country, nice beaches/ocean and folks but not a whole lot more. worth a month or so.