Mid to late July is primetime around POW, your hitting the tail end of the king season which means the numbers may be down a little from June and early July fishing but the size avg. is better, you will also be getting into good numbers of silvers and limits (6 per person) shouldn't be difficult. bottomfishing stays pretty consistant from June thru Aug.
At the resort I work at the last 2 weeks of July are fully booked by regulars who have fished with us for years, not much chance of getting in unless someone dies.
Stream fishing should also be excellent with silvers and sockeye showing (few if any kings return to POW rivers) in good numbers and trout fishing is always good (atleast in my experience)
IMHO, you couldn't pick a better time to fish P.O.W. Is. Good fishing!