Pirkei Avot provides good guidance for this answer in several areas:
The end of Chapter 6 (Well, OK, it's actually a Braita, not part of Avot, but, it's called "the 6th chapter" in our Siddurim) advises that one should live only in a place that has Torah people.
There are several other places in Pirkei Avot that mention interactions with people in various ways such as:
"In a place where there are no people, strive to be a person (man)."
Be like Aharon by pursuing peace and bringing people close to Torah.
So, to do this, I would start by viewing the statistics regarding the Jewish population of the 3 states that you mentioned.
Clearly, you can see that between 1899 and 2018, both Alabama and Alaska are near the bottom of the list n terms of population growth - 0.2 % and 0.8%, respectively. That doesn't indicate much of a good environment for being in a Torah type community. Yes, I understand that Montgomery and Birmingham, AL have some shuls there, but it's still tough to find a solid Jewish community where Torah is expanding. My point is, that if you're going to try to bring people to Torah, you have to have as many Jews around to do that to maximize your potential and success, right?
Alaska is a poorer Jewish environment than Alabama. I think Fairbanks has a shul. Someone from my neighborhood was there about a year ago and told me that they barely get a minyan, and in the entire state, you won't find many Jews. Worse, look how much barren land is in Alaska. Yes, it says, "In a place were there are no men, strive to be a man." But, really ... have you ever been on the Klondike Highway in February during a blizzard - quite common?? Forget about "striving" to be a man - you're more concerned about surviving to be a man!
So, now look at Pennsylvania. They had a 2.3% population growth. Now, that's significant compared to the other 2 states. Plus, look how many Jews are in Philadelphia and Pittsburgh, alone. They speak for themselves! Not only is it easy to live in a Torah place, but alos, not only can you be a man, you can be a shtarker quite easily.
In summary, your analysis is correct. Pennsylvania is the only one you can live in.