...when it gets a bit later in the morning, I'm sure you'll have plenty of folks chiming in, but to get a couple thoughts out before I go to work:
- Many of the tourist facilities (campgrounds, etc) up here close by mid-September;
- Depending where you travel (i.e. Fairbanks and beyond or just in Southcentral AK), you'll likely see cooler temps and possibly snow/ice by late September, although winter is a fickle creature lately
- Several roads in Alaska are on the "don't go here" list from the rental companies: I'd check carefully, but I believe that most rental places ban travel on the Edgerton Highway (road to McCarthy / Chitina), the Denali Highway (road between Paxson and Cantwell) and the Haul Road / Dalton Highway (to the North Slope). That's unfortunate because the Denali particularly (IMNSHO) is one of the most scenic drives in AK. I'm not sure about the "banned" status of Taylor Highway (road to Chicken / Eagle, both popular destinations), but I believe it runs the risk of being weather-impacted, although probably later than September.