Ret, Welcome to the Buzz.
Sounds like you know what you're after and I can respect that you're willing to take it slow learning. If you forget camping and hiking,there's also the Colorado between Grizzly Creek and Debeque
. For your fishing cats there's plenty of mellow Class II floating. If you do it right you can pull ashore at the riverside motel in Silt, have the continental breakfast, fill up yer coffee mug and keep right on floating to Rifle!
The Upper C at lower water would probably be the best bet locally, below Rancho, possibly with a portage at Rodeo, and some good scouting at Pinball. Check in with one of the Buzz's newest sponsors, Colorado River Rentals
for a full oar rig, or y'all could probably have a great time R-2ing a paddle boat with your gear down the Upper Colorado. Take earplugs for camping on the Upper C, though.
Scott - I respectfully disagree, but Ret's aren't ready for Brown's with those rigs or a rented raft, and I'm glad to see him say so right up front. The Milk Run from Johnson Village to Ruby Mt., maybe, not Brown's. Another stretch on the Ark would be Big Bend to Salida, or down by Cotapaxi there's a pretty "uneventful" stretch that would be a good float and where they could snag a fish or two. Tough to find camping down there, and you won't be able to string together the mileage you want without some Class III rapids.
That said, I did get to see big ol' Jesse (K2andCannoli) run Westwater on his little cat before he upgraded to a real whitewater rig. I thought for sure he'd need a snorkle and we'd wind up carrying him and the shreds of that cat out but he did just fine.
I don't recommend any of the above stretches at high water in those boats.
Have fun and be safe!