I'm GMing Fall of Plaguestone, and I can say that she just run the village inn / tavern / general store, and, some spoilers down bellow:
Delma's family is is related by blood to the village lord, that died just after the founding in a fire.
There is about 300 people in the Village, but nowhere is said that there is no generic shops or npcs that can make something if asked for.
The last priest died at the plague and the local Erastil shrine was left alone.
Lastly, the village main produce is turnips, as the bitter, corrupted soil is slowly killing the plants there.
A great deal of infos came from the hooks in the adventure backgrounds and minor quests and interactions with the npcs.
My group just finished the AP and the last battle was super easy as our soldier attacked Serovox three times and got two critical hits, leaving them almost dead and burning. Just after this, our solarion charged and misses, but Serovox tried to get away from him and provoked an AdO (the solarion had all the step up feat line) and died before doing anything!
The gatecrasher tanked four whole turns after it, until the technomancer used grease and it fell.
The batlle was so good that the players loved how they finished the invasion Just as they planned.