That's a pretty tall order. Most all rivers will be closed to king salmon fishing when the silvers arrive. The kenai runs will overlap the last week of July, as well as pinks and Reds, though. The kasilof will is another one that would be open, but I don't recall seeing anyone "flyfishing" either one, especially in that timeframe because of high water and heavy flows.
Chuck and duck is more the norm on those rivers if you're on the bank.
If anything, fly into Anchorage and rent a car to have options to move around
