My favorite Pokémon is Hippowdon but, honestly, i'm not sure how useful it would be in that scenario...
I'd probably take a Pokémon that can get me across long distances fast, or maybe one that would ensure the journey would be comfortable, in which case...
I'd pick Tropius!
Cause it can fly around carrying me over, AND grows bananas you can eat if you are ever short on food ^^ <3