I attended a talk last evening at the local chapter of Trout Unlimited. Matt McCannel (Head Fly Fishing Guide/Umpqua Fly Designer/SIMMS Ambassador/Sage Ambassador) gave a talk on his company's (RIGG's Fly Fishing in Montrose, Colorado), guided float trips down the Gunnison Gorge - which is below what people think of as the Black Canyon of the Gunnison - but in reality, is the same canyon and river. The portion they run is 11 miles below the last dam. The significance is a huge river chock full of (80% density?) of enormous, trout both browns and rainbows. I mean, 20+ inches.
My husband and I commonly float fish the Gunnison from the base of the gorge at the confluence of the North Fork. (We check for flows and visibility conditions because the North Fork will "blow-out" and cloud the river below the confluence to the point that the fishing is off.) That said, one can always park at the confluence and hike up into the gorge.
Matt's company will pack you and all the river gear for a multi-day float trip by MULE down Chukar Trail. There are other pubic access trails, as well, for foot travel only into the gorge and campsites one can be reserved in advance. Then, a hiker can fish for miles in either direction providing the flows aren't overbank. Call Riggs fly shop to get their advice prior to one of these hiking / camping / fishing trips before hand.
We have never accessed the gorge from these trails. We usually drive up river from Delta, set up camp along the river, then put in at the Gunnison River Pleasure Park at the confluence of the North Fork and float all day down to the Orchard take-out or a couple miles down river of the diversion dam bypassing Orchard and getting a couple more lazy evening miles in before taking out in a corn field leased by the Pleasure Park.
I learned a lot from Matts talk about fishing that river and I can't wait to go back and try some of his unique methods, like using 30 lb mono filament as the leader... crazy.