This would be so much fun!
The Sims 4 is missing out on quirky situational gameplay by leaving out a chance encounter with Bigfoot / Yeti. If they don't refresh Outdoor Retreat, I'd love to see this character make an appearance in a future rugged outdoor pack, as well as Bigfoot showing up in your suggested worlds (if toggled).
Make it into an Aspiration Mystery to solve "Finding Bigfoot". Track their giant footprints and make plaster casts of them. Leave them offerings on a forest tree stump. Befriend them to unlock a new Trail Mix recipe, or unlock a new howl for Werewolves. Even craft a Bigfoot statue on the woodworking table.