I'd heavily consider water and defense. Both foci have nice enlivens for exploring. I personally had some of my best exploring with water major, defense minor. Utility is a good, Offense isn't all that good for exploring because of so little inherent defense. Air can be offense or defensive but there are certainly offense and defense forms that exceed them. So, as suggested previously, defense defense is an option, and defense water, and water defense. Again, I prefer water/defense because of the variety in enlivens. Being able to take my diamondback under water was super helpful.