I did a trip to that area a couple of years ago, starting and ending from Elkhart Park trailhead, and basically circumnavigating Mt. Quintet via Angel pass and fishing all of the lakes along the way. Our trip was also in mid August. I did a lot of research beforehand and had some pretty reliable reports that many of these lakes and others in the surrounding area were good golden lakes. We talked to one of the employees at the great outdoor shop in Pinedale on the way in and he confirmed many of the reports that I read, but stated that usually August isn't the best month to go for goldens, especially if you are going to be fishing from shore. Apparently, in mid summer the golden tend to all go deep to the center of the lakes and are really tough to fish for. He said that for that time of your, our best bet would be to pack in a float tube and a sinking line and use fast sinking scuds as, and that shore fishing would be pretty non-productive. We already had the trip planned at that point so we went for it anyway. Turns out he was correct, as we managed to get some smaller goldens from the creeks connecting the lakes, but it was much more difficult fishing than I expected. And we passed by some gorgeous, very fishy looking water that were basically devoid of any fish, at least when we were there. It was an incredible trip with some of the best off trail travel that I have ever done anywhere, but the fishing (at least for golden) was overall a little disappointing. So if fishing is priority #1 for you, I'll give you the same advice as that employee at the great outdoor shop gave me - to get back to that area at ice off in July or wait until mid September, as the fishing then will likely be much better.
It's still a very worthwhile trip and I'm happy to share more details if you would like so PM me if you're interested. As far as I know, there isn't any easy way to access that area. It's really out of the way and takes 2 full days minimum just to get to it just about any way you shake it. So unless you're hiking machines and can really pound out the miles, I'd plan a solid week at least to make your time there worthwhile. I'm headed back to the winds (through the reservation side this time) myself here next week so I'll let you know what I find. We're going to a different area this time and not targeting goldens, but you never know what you'll find.