There are lots of places you can get mellow riverrunning in Colorado. I don't know what's close to "Nunya," the location you've listed on your profile, but putting your real location would help folks recommend runs for you that you don't have to drive for half a day to get to and could even help facilitate meeting likeminded folks in your neighborhood.
Check out the Yampa above Deerlodge Park, the White River, the Colorado below Newcastle, the Lower Blue. The South Platte through and below Denver, the Arkansas below Canon City may have some mellow boating. Go buy a guidebook. Talk to folks at the local canoe, kayak, or raft shop. Get in touch with canoeing clubs.
And check this out: Jerry's Local River Guide