Jack made it clear that you can just use bears.
I utilize this all the time in general handwave fashion, but when I specifically run Into the Odd/Weird North/Cairn/Monolith etc, I've landed on a three-tier measure of NPC power so as to better represent varying tactical levels of possible encounters. It's not rocket science, and it's not perfect, but it's what I do and it's been nigh-on effortless for me for years now.
There are three NPC statlines, and that's it. Ever.
|Obligatory image because blogpost. Also because Stepan Alekseev. Artstation.|