White water rafting is a major tourist activity in the Grand Canyon, and floating down the river on a guided adventure for a week or so is an incredible experience. While not all of the river is classified as white water, there are enough places in the river where you have to hang on for dear life to give the full experience of white water rafting.
The scenery at the bottom of the Grand Canyon is magnificent, and a guided tour of the river is a great way for the novice to start white water rafting, and see if it is an adventure to pursue with zest. The tours of the Colorado River are complete packages. They provide all your food and beverage items, but you will need to bring your own sleeping gear. Going down the Colorado River by white water rafting is something to do while you are physically able to.
There is a book called "Down the Colorado" by John Wesley Powell, who was the first white person to explore it, and if you want to do some white water rafting in the Colorado River, this book is a must read. His courage was extraordinary.