You might want to sift through my post about an Alaska Honeymoon 10 threads or so below yours, and roughly 1 month before you (Aug 3rd - 12th) We have very similar goals.
Affordable places I found in some of the locations:
Denali Fireside (Talkeetna)
McKinley Creekside Cabins (Denali)
I am also staying at Alyeska and Captian Cook, but those arent affordable catagory.
I really wanted to see glaciers, but 26 glaciers seemed excessive to me. We also really wanted to do the Kenai Fjords. I opted for the Kenai Fjords trip due to the wildlife with the addition of 1-2 glaciers. Being on the water for 5-6 hours on back to back days would get to me. Just something to consider. FTI and others conviced me to lose a day and add it to Denali because 1 day does not do it justice. After talking to numerous people who only did 1-2 days on a cruise-tour in denali, I am glad I added days up there.
In my thread the consensus seemed to be if the Mountian is not out, there really isnt much fun in going past Eielson visitor center. Get off the bus and enjoy the park. Rain or shine we are planning on doing 2 days of quite a bit of hiking in the park, and 1 day of hiking near the entrance.
I cannot comment on most of this as I havent gone yet. But I plan on doing a trip report and can give you any feedback when I get back from mine.