Through the Foglands by Maynard (itch.io)

Foglands is primarily a wilderness point crawl adventure. It’s designed to give players a simple goal: move from left to right as fast as possible. A warlord blocks their path and demands 2,000 gold to proceed. Parties can delve into a dungeon to raise the cash, go the long way around (through a perilous swamp), or fight their way through. Two rival expeditions race them to their destination.

Foglands was designed (and redesigned) while I was playing a lot of OSR content, so it incorporates many of those principles. This is the most fun I've had playing 5th; giving players a simple problem and letting them figure it out in a giant sandbox.