I used to use my traditional-for-Disney-trips bucket hat, which did a good job of keeping the water off the camera and I could quickly cover the camera when needed. The bucket hat is good for photography as it doesn't have a bill to get in the way like a baseball cap! (When you're holding the camera up to the eye.) With Splash Mt, it's not like you're constantly getting hit with a firehose of water, there are just a couple spots where you need some protection and only for one or two quick splashes, which should not be a huge problem to protect your gear from.
Nowadays, though, I just mount a weathersealed lens and let 'em get soaked.

I'm still dreaming of a weathersealed fisheye...