Dillon Lake Water Sports is a very nice rental shop for canoes, kayaks, and other items I'm forgetting. You're given the choice of multiple boating trips you can take, all with varying prices. Once you make your selection, they'll personally drop you off at the launch spot with the rest of your group and let you begin your voyage. You're given an allocated amount of time to get from point A to point B. If you tell them at the time of drop off that you'd like a little more time to explore, they'll gladly oblige. Once you reach the end of your trip, they'll be there waiting for you. They; even load your canoe/kayak up for you and take you back to the store.
Very fun and highly recommended.