[@ClocktowerEchos] Ideas on the Northern Marshes? Sure. 

The name implies something about the landscape. Do you have some set ideas on that?
Looking at the region I like the fact that the lands have the longest border to defend to the  North, and the longest shore to defend. Seems natural to go for a rather martial society. The region is relatively small to be responsible for such a big defensive task for the 5 Crowns. So, besides the standing army and navy, military training and service for all who come of age seems necessary. I read somewhere that New England was and is a progressive region. In keeping with this tradition women will also undergo military training. This will have an effect on the equality of women and men in society as a whole. 
Initial keywords: Frost corroders (Northern border garrisons), incorporate Red sox, Navy seals? Berserk units (shock troops, guerrilla fighters, male fighters, female officers?). All female units?  

I’m thinking with ‘cool outside, warm inside’ in mind, that the society is heavily (over)regulated. Bureaucrasy will be all around. Discipline, practicality, an aversion to idleness and luxury are further values in Marches’ society. Rules are also there to handle the ‘warm inside’; it takes a while to break a northerner’s cool and collected exterior, but when it cracks...it bursts! Wild bursts of berserk rage are, sadly, not uncommon. Crime passionelle account for over 85% of all crimes in these lands. 

There is a military academy somewhere in Maine, near the capital, where strategy is taught. 

Vermont: renowned for BREWERIES! 😋
Maine: blueberry liquor, nickname inhabitants related? ‘purple lips’? 
Many drunks in society? Contrast between tight discipline and wild drunkards? 

Okay, these are my initial ideas anyways. 😅