I have a pair of Keen hiking sandals that are very comfortable. I have mostly worn them when I've hiked in the mountains (Smokies and Glacier.) Would I really need something with more ankle support? I do have boots and it will be the first of October so I'm not sure which would be the best to wear. Keep in mind we don't plan on hiking all the way to the bottom but we do want to get "below the rim." So what are your suggestions?