Encrypted message in Simpsons Christmas episode 2013

I'm doubting that we'll ever get an answer (at least not any time soon) unless we collaborate on this one, so I figured it'd be good if someone set up a wiki post for everyone to contribute to. I've made the references that have already been cracked bold to make it easier to distinguish them from all the others.

If you have any ideas or actual answers, then feel free to update this post with whatever you've got!

First in freeways - 2H77JE

Possibly on hit on North Carolina's "First in Flight" license plate slogan. Well: "North Carolina has the second largest state maintained highway network in the United States[...]", but: "North Carolina Is The Good Road State" (https://www.ourstate.com/good-road-state/).

The 'yuh-huh' state - 7BMA12

Have an idea of what "The 'yuh-huh' state" may refer to?

Jewel of the fracking belt - DX156A

Have an idea of what "Jewel of the fracking belt" may refer to?

Still a British colony at heart - 1FGFI3

Have an idea of what "Still a British colony at heart" may refer to?

Land of many water snakes - P1VM8L

Have an idea of what "Land of many water snakes" may refer to?

The socks and sandals state - 23IEZ01

Have an idea of what "The socks and sandals state" may refer to?

The crooked governor state - 1PLIT4

This seems to be a reference to Illinois as 4 of their last 7 governors have been convicted for fraud and/or corruption. The colors on the license plates are also identical.

First in foreclosures - 1AVN86

For 2013, this would be New Jersey (2nd place Florida, 3rd place New York). Note that the license plate serial would not be valid for new Jersey...but OTOH it looks like none of the license plate serials match some state's license plate serial format).

The wait and see state - 13NR14

Have an idea of what "The wait and see state" may refer to?

Touch it with a stick state - 2H45LX

The touch it with a stick plate refers to WV, referring to hillbillies being dumb, so when finding dead things they poke at them as pictured in film and TV. The license plate is blue and gold, just like it is in West Virginia also.

The land of loud talkers - SABI7F

Have an idea of what "The land of loud talkers" may refer to?

The bee sting state (dec) - J111A1

Utah is the "bee hive state" (they also has bee hives depicted on license plates at some time).

Home of the other clam chowder (feb) - LTOU12

This may refer to the state of Rhode Island, which has its own style of clam chowder featuring a clear broth rather than the more common cream-based "New England clam chowder".

The pickpocket state - LL158Z

Have an idea of what "The pickpocket state" may refer to?

The sunburn state (aug) - 6HGF17

A pun on Florida's slogan "Sunshine State".

America's second-greatest Carolina - 21PIR9

Have an idea of what "America's second-greates Carolina" may refer to?

Unique left turn laws - 1DXV4

This does indeed seem to be a reference to the "Michigan left", giving us Michigan as the state.

America's Mongolia (jul) - 32UVL9

Have an idea of what "America's Mongolia" may refer to?

Where soda meets pop - 7IDAF1

Have an idea of what "Where soda meets pop" may refer to? The soda/pop dividing line in NY is somewhere between Syracuse and Rochester.

This is not an answer or solution, but it's too long for a comment and it might help in finding an answer to this. Sorry if this was inappropriate to post as an answer.

The Simpsons have been known to hide lots of mathematical references in their show (also see The Simpsons and their Mathematical Secrets by Simon Singh, who incidentally also wrote a book about codebreaking).

If this is indeed some kind of code/reference I'm suspecting this is not the only set of codes in the episode. (I might scan the entire episode for more stuff like this later this week).

My first guess is that these are indeed references to US states, which means that some of the answers could be guessed / deduced, leaving us with a partial set of codes and answers. From there the actual method of decryption could possible be deduced, enabling us to solve the rest of the states. However, if these are all just states that wouldn't leave us with much of a puzzle. Hence my reasoning that there is more to this (if at all).

If the codes are indeed states this is not a simple substitution method, where the length of the encrypted text would be the same length as the answer. If it were a substitution code the answers would be truncated to the 6 characters we see, making it a lot harder to solve than with the original lengths. It's possible, but not very likely.

One method of encryption this reminds me of is MD5 (which renders any length of text as a 32 digit hexadecimal number). However, these strings are only 6 characters and seem to use all letters (as well as numbers 0-9) so it's not hexadecimal. It could technically be anything from base 36 up, but as I think it's not a substitution cipher I don't think it's a direct translation from text to any base x format. Then again, MD5 isn't either, so there's probably other known methods of encryption that render fixed-length sets of specific characters. I don't know of any off the top of my head.

Honestly, I think the first step towards a solution is see if we can find a set of answers that might fit the descriptions, like the US states, and see if there's a correlation between the answers and their respective codes.

Unique left turn laws - 1DXV4

Michigan has them (referring to the "Michigan left").

"Home of the other clam chowder"

Rhode Island - see https://cooking.nytimes.com/recipes/1016718-rhode-island-clam-chowder