A "leap to Flowrestown" won't be manageable. Pian en Luries will have to expand northwards slowly to reduce spawns, and a prodigious sum of adventurers will be necessary around those mountains.
As tempting as Flowrestown is, I remain convinced that the most realistic "next step" towards colonizing the Divide Mountains is Sallowtown, or maybe Unterstrom. Actually a join colony in Sallowtown between the Lurian Kingdoms and the Véinsørmoot would be very interesting.
Except that the Lurians always make sure to remind D'Hara just how unpleasant they are every time we start forgetting. The idea of a lurian-backed colony in Sallowtown would not be met warmly in D'Hara...