Rent from Confluence Kayaks in Denver 303-433-3676. They are located across the street from the Confluence WW Park. They have kayaks, SUPs, and equipment. You can rent paddles as well. You could bring your own base layer options and rent the boats and paddles from them. Call them to see if what they rent will meet your needs, ask for pricing, and reserve what you want. Great shop that would love to support your trip. You can find water flows for the park on this site on the Flows Tab Above. South Platte River, Confluence Park. But, remember there are 14.5 miles of man-made whitewater coming through Denver.
I love to dance, but who needs the music- It throws me off.