Having tried a colony in Flowrestown I can say that it's not that simple. The geography is a bit oppressive as the expansion direction is rather awkward with the Balance's Retreat mountains splitting any cohesive region borders. Flowrestown also requires quite a bit of food, being fourth overall (I think...It goes Darfix, Giask, Golden Farrow, Flowrestown, something else, don't care...)
I also had that stint in Ordenstaat with Rettleville. That was also rather difficult, for the aforementioned reasons of monsters. Oh yeah, and there were some really strange dealings and counterdealings. To make the story relatively not complex, Milmice talked to Garret, Garret tried to play Milmice, Milmice vowed Garret would be dead or something, Milmice got executed. Arden found out before Milmice died about Garret's supposed dealings, called him out, Garret got mad and messed up Rettleville then left. Arden vowed to hunt down Garret and his descendants or something, then Arden died or something after his fiasco in PeL. Meh.
Ok, so basically, Rettleville is a pretty darn tough place to maintain, even though it isn't too bad once you get the security. Its regions are pretty easy to feed, assuming you can get the food to the peasants' mouths and not the monsters'.
