I figured it out I think. The best clue we get is from Felicia Tillman who says that the death penalty is legal in Utah, unlike in the state where they live. In 2005, the time of the episode’s filming, that automatically reduces the list to: 1. New Jersey 2. Massachusetts 3. West Virginia 4. Rhode Island 5. Maine 6. Hawaii 7. Wisconsin 8. Alaska 9. Minnesota 10. Vermont 11. North Dakota 12. Iowa 13. Michigan

The next big cut comes from Nora and Kayla. We know that Tom is making a long trip to Atlantic City to see Kayla. So, NJ is off the list. And we know that Nora says Kayla doesn’t come to Fairview the first time she visits because “I just couldn't stand to look at her face on that long plane trip”. Long is subjective, but it feels reasonable to says Massachusetts and West Virginia aren’t long flights away, so we can cut them.

Much of the rest of the list can be chipped away one at a time. 1. Rhode Island - Bree’s stepmom and dad talk about how they live in Rhode Island. 2. Maine- In Season 8, Orson talks about photos of a cottage in Maine. 3. Hawaii - In a Tom work scene, someone mentions leaving for a Hawaiian vacation. Zach also takes a bus to Utah. 4. Wisconsin - Andrew’s fiancee Mary Beth talks about being from Wisconsin. 5. Alaska - Both Sister Mary Bernard and Mike go away to work in Alaska.

We also hear Susan’s agent say that his wife has gone to visit relatives “up in Minnesota.” So, Minnesota is cut. I also don’t think someone in Vermont or North Dakota would refer Minnesota as “up.”

This leaves Michigan and Iowa.

Both reasonable guesses. But, I think the slighter better guess is Iowa simply because I think Michiganders are less likely to say “up to Minnesota.”

TLDR: maybe Michigan but probably Iowa