I didn't get to hunt, but the wife and I spent 65 days camping in Alaska last summer. We were prepared for hordes of mosquitos, but we only saw really bad bugs a couple of times. Since it poured rain for most of our trip, we guessed that all the bugs drowned. We only got as far north as Fairbanks, so the north slope might be a different story, but our worst bugs were in Denali, and for a couple of days there it was headnets, long sleeves, and Therma Cell, which made it somewhat bearable. We saw frost in central Alaska in late July and early August, so by the time you are going, the bugs may be down.
An Alaska hunt is most definitely on my bucket list; you will see some awesome country. Be prepared that hiking the muskeg and alder country is grueling, even on fairly flat ground. If you are successful in getting a caribou, know that it will probably be hard earned. Alaska is truly the Great Land; enjoy it in all its' glory.