The Colorado River from Moab to Hite is known as Cataract Canyon. It involves rapids up to class 4 (out of 5) but can grow to class 5 during high spring snowmelts. A permit is needed from the NPS due to passing through Canyonlands National Park.
It is flatwater for about 50 miles, then about 30 miles of rapids, then about 30 miles of flatwater.
The trip is floated in about 6 days, or with a motor in about 3 days. You must follow all NPS enforced safety rules restrictions and gear.
The low water takeout is before Hite on the north side of the river near highway 95.
Check out the Triplog.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.