There was, in fact, a tiny western possession of the Russian Empire that escaped the list: the German town of Jever (now in the Friesland district of Germany), which was Russian up to 1818 because of complicated dynastic stuff (then they gave it back because it was pretty meaningless to have).
As far as I could calculate, this still isn't enough to bridge the gap; it does make the margin as close as 15 minutes - but still no endless sun
I suppose that, between Alaska, Maine, Hawaii, Philippines, US Virgin Islands and the American occupation zone in Berlin, there could've been enough US territory to just about make a full year of continuous endless sun at some point in 1944-'46. But I didn't do much calculation, and couldn't find any definite dates for the Berlin occupation anyway.
There are two films that I particularly like.
One of them is a science-fiction dramatic comedy involving a boy who accidentally travelled in time. Extremely popular when it originally came out in 1985, it retains a major cult following to this day.
The other one, of course, is Back to the Future.