Here's another attempt at a simple way to engage players while they travel the wilderness while making different types of terrains feel different. (Maybe a better name for these things would be Terrain Challenges, or Travel Challenges Simon?)
This might be the simplest one yet (I'm sure the seed of the idea came from Zak's critical range choice he gives his players):
If you have any of the folks at the bottom in your party they can shift one box per day as well.
Depending on how you check for monsters and getting lost you might want to cut each side down to 3 boxes. I'm assuming a d6 with results on a one, so you would never completely avoid the chance to have encounters or get lost.
No players will want to get lost, but I'm thinking low level characters may push towards safety just to survive. Hopefully they will stumble upon a road or an interesting ruin before they are finally eaten alive.