I like the fall which starts in late August. It is possible to see great Northern Lights by Labor Day up by Fairbanks. The day length is surprising long due to the length of twilight. Fewer tourists, animal activity, less bugs, and cooler weather. It feels more like Alaska.
There is a seasonal shift in the Interior after Labor Day. Many people have finished their seasonal jobs. They get busy cutting firewood for the long winter. Many focus on subsistence hunting and getting a moose. I don't usually pay much attention to tourist attractions but I enjoyed the Follies in Ester, which involves some Robert Service poems. Gold panning the original paydirt up by Fox was a lot of fun. I liked the Interior more than I expected after 9 trips to the Coast. The people are great. Sourdoughs and Athabascans alike.