I tend to agree with countr21. Like anything you can go too far. If you are one of those guys you see at they gym that have so much muscle they can't lift their arms over their head or put their arms down to the side of your body, I could see that causing some serious issues.

However being in good shape overall with a reasonable amount of muscle will absolutely make your trip more enjoyable. You will end up being tired less, and will recover faster. I would recommend that you put a particular focus on cardio, legs, and back. In that order.