Almost all hand held GPS units are waterproof, I know all Garmin and Magellan units are, I don't think I have ever seen any that come with a mounting kit, however there are many companies out there that make a bracket, you can even use certain universal cell phone brackets to mount them to your handlebars. As far as the cooler I have seen some (they have a really nice one at Gander Mountain, but I don't think you have any of these stores on Arizona) with mounting hooks that you can hold them down with ratchet straps or bungee cords. I have seen people just ratchet strap regular coolers to there rear rack.