I highly recommend the 3-way mount--- I didn't use the "long stick" that is one of the three ways here, but mounted the camera on the short handle part and carried that around most of the time. I also purchased a wrist strap for this (like one for a microphone or Wii strap), and it was what I used 90% of the time at Disney. Made for some wonderful footage, wasn't in anyone's way because it's just a short hand mount, was safe, and captured our memories.
Also would suggest getting the "jaws clamp" mount. I clipped it on the teacups center "steering wheel" for some amazing footage (different since the camera is stable and spinning opposite of you). I could also clamp it to the carousel handles for fun shots of my son's face.
(Both mounts are GoPro brand on their site or
Amazon).
Agree with previous poster-- also learn how to turn off the red light and sound for other guest's enjoyment of the experiences too.
My GoPro videos are so special to me from our trip this year! They capture moments and experiences that stills cannot (though we love our photos too of course), and helped share the magic with others when we got back.
I would advise buying your camera in advance if possible... I purchased mine 8 months ahead and was very glad I did. The more practice you get-- making little videos, trying new features, and learning your editing software-- the more natural it will feel using it at Disney. I was in the moment during our trip, and not trying to figure out my new technology the whole time.
Have fun!!