Pending flows, which I haven't checked and are (as noted) likely still in the runoff zone, the Ark is a pretty darn sweet river. I have a work trip in CO Springs each August and spend 3-4 nights camping on the Ark afterwards, hitting the DS on the way in and out. Outside of the meadows up top you probably won't encounter another angler at all.
You've got Hayden Meadows up top, which can be lights out if a hatch is happening, then a hell of a lot of good pocket water and runs down to Buena Vista (a pretty cool town in its own right) with plenty of access along the way. Much of the area along the road upstream of the Railroad Bridge campground near Buena Vista is BLM and available for free dispersed camping, too. If you get the chance I'd highly recommend it (again, pending flows). I can't speak to this time of year but in Hayden Meadows I'm doing whatever is hatching and/or a hopper; downstream I'm generally doing a hopper/dropper or an indicator setup.