I think that August is a great time to go. Usually great weather. In August I've fished Homer for Halibut and Lake Creek for Silvers. Toured Denali and Talkeetna, Seward for glaciers, float planes over the Kenai and ice fields and lots of the area between Denali & Anchorage. Also, every trip has included time in Anchorage. Driven through much of the Kenai.
I was born and raised in Manhattan and I look at Alaska much the same way as I look at New York City - you can never see it all and do it all, but it's sure fun trying.