Hah! We canoed some stretches and live within 140 miles of the Yukon River. I think you should do some serious research. Much of the Yukon Riverbank is cliff, at least from it’s source in the mountains of BC as far west as Nulato.
If you want to hike along that river, consider going during the winter when the river is a road, but expect some serious weather. I like the idea of the Canol Trail and hope to hike that some day.
You also might want to consider a hike in the Arctic National Wildlife Refuge. It’s rugged. It’s remote. And it’s about to be drilled. Some do it every year taking a different route as there are no trails. They usually end up in the villages of Ft. Yukon or Arctic Village.
If you want to talk to someone who likes to hike and lives along the Yukon River, send me a private message.
Pound Hound