I have lived in the Mat-Su valley for almost 14 years now (about 40 miles north of Anchorage and 350 away from Fairbanks). The light thing is not such a big deal this far south but way, way up north it can be difficult, although I have to say I'm pretty excited about the solstice and now gaining light. We like to hike, but that's about it for outdoorsy stuff. Of course, it's beautiful and even in its harshest, there is a stark, majestic beauty.
All that said, the people keep me here. Ya know how everyone is complaining of holiday shopping because people are rude? That hasn't been my experience. People still smile, let one another go first and generally behave well. I can't tell you how many times I've pulled a stranger out of a ditch and thankfully, they've done the same for me. Someone is always there to help. At least, that has been my experience where I live.
My daughter went to UAF in Fairbanks and, I think, they have the biggest temp swing. It can be in the 80s in the summer and then dip to -35 in the winter. I don't really have much to add on Fairbanks, I only visited.
I know the temps sound extreme, but I grew up in NE Ohio and I think it is MUCH colder there with the biting wind. I know they all say it, but it's a different kind of cold.
All that said, do some research. Anchorage is a good place to start. It's a city with all the city trappings. A bit north is Eagle River, Peters Creek and on up to the valley. Then there's places like Bethel or the MANY villages. It's a state with a bit of everything when it comes to living conditions.
And as long as we have lived here, gosh darn it, we still oohhh and ahhhh over the many mamas and babies moose strolling through our yard, or the ptarmigan standing stupidly in the road, or that eagle that looks down off the tip of the tree down KGB (a road). I'm struck anew every spring by the medley of wildflowers. They're truly so beautiful.
And as someone else said, what's the worst that can happen? You hate it and move back? Sounds like an awesome experience anyway. Good luck!