Bravo
The web site below is one of many that gives general schedule on when the various salmon runs occur on the Kenai. King Salmon on the Kenai river comes in two runs: one mid May to July and the second one from early July to early August. Plenty of places to catch rainbow, just ask around. In terms of salmon, don't just limit your self to Kings -- Reds and Silvers are beautiful fish and probably better eating then Kings, and you can catch more of them. You sure don't need a river guide to catch fish in Alaska.
http://www.alaskafishingak.com/kenai/ke ... salmon.htmAnd I'd caution about that coastal route from Bellingham to Ketchikan -- weather, lack of places to put down, and rugged terrain make this a risky rout for small airplanes. Most people fly the highway and have a lot of fun.
At any rate, have fun and come out to McCarthy for a visit.