You would have plenty of time to include Girdwood, Seward and Homer. I would not "base" yourself in one place though.
Book a rental car for Anchorage NOW and also look at off-airport locations.
I would arrive July 29, spend the night. Then July 30 spend time along Turnagain Arm (Girdwood and other places - Potter Marsh, the turnouts for views, Wildlife Conservation Center, etc) then drive to Homer. Spend night of July 30 in Homer. Take some boat tour on July 31 and maybe after that drive 4 hours to Seward.
Aug 1 take 6 hour or longer Kenai Fjords boat tour, then maybe August 2 do hiking near Exit Glacier or a kayak tour or fishing, etc. Drive in the evening to Anchorage, arriving at the airport before midnight for your 1.50am departure.
You could also go to Denali NP instead. Also, the 49th State Brewery in Healy has a microbrewery. Their sister restaurant, Prospectors Pizza, has 49 beers on tap (49th State may also have the same 49). If you went here, July 30 drive to Denali (about 5 hours), July 31 take a shuttle bus (not a tour bus) to Eielson. August 1 maybe go rafting, ATV tour, etc. Maybe also drive the first 15 miles of the park road. Head to the brewery in Healy, etc. Aug 2 you can drive the first 15 miles of the park road, go to the visitor center, watch the sleddog demo, etc. then head back to Anchorage in the afternoon.
More a matter of personal preference than anything. But with your priorities of nature, scenery, wildlife and microbrews, I would choose Denali over the KP.