You should be arriving at about the begining of the silver salmon run on Susitna River streams north of Anchorage on the Parks Hwy. There are also runs coming in on Seward Hwy. streams south of ANC, but the traffic down there is horrid. It's the only road leading to Kenai Peninsula. I hate the place during the summer. The Parks Hwy. isn't much better, but it tends to clear after you get past Denali Park.
Weather is quite pleasant during the summer with warm days and cool nights. You should bring a light fleece lined jacket as the temps can drop if stormy weather approaches.
My next question.......Why the Hell Anchorage? That's nothing more than Seattle North. Fairbanks and the interior is where the real Alaska is located with better weather and more interesting history to boot.
However if you insist on Anchorage here's a couple of places to visit......Alaska Native Heritage Museum out on Tudor Rd. and the Aviation History Museum on Lake Hood.
Ya hafta go and have either dinner or Sunday brunch at the Sourdough Mining Company and dinner at the Glacier Brewhouse. Take a day and drive up to Palmer and Wasilla. All the good salmon streams are above Wasilla starting at Willow. Even if you don't get a salmon, there are are rainbows and grayling in the streams. I've seen HUGE rainbows pulled out of Willow Creek. Egg patterns on a fly rod work best.