If you want whitewater rafting go to Jackson WY outside of Teton NP. They have a great all day float down the Snake River. First part of the day is a nice scenic float you will see all kinds of bald eagles. The second part is white water with class IV rapids also with beautiful scenery... There are all kinds of horseback riding. We did an evening ride with a dinner fun times. I agree with just stay to the north. Zion and even Bryce can get hot in July. Save those trips for spring or early fall. I have been to both many time and IMHO that is the best ime to go.