D@W: Campaigns has a lot of good stuff about calculating how quickly construction projects can be completed based on the number and skills of people working on them, but, when there’s a small population to draw from, how do you calculate the number of available civilians to put on the project? Any mercenaries, conscripts, and militia can obviously be assigned to the task, but it should also be possible to hire more help than just the military.
(As background, my players are currently running a one-hex mini-domain with a total of 104 families (29 peasant farmers, 75 in a just-completed village). They want to expand the stronghold and secure an additional hex to provide a little room to grow, but they’re on an isolated and untamed island, so just pulling in workers from a larger population center would be non-trivial. Getting the assumed 3,000 workers to expand the stronghold at 500gp/day is looking pretty unlikely!)
Also, are agricultural improvements and urban improvements (to draw in more population) considered to be construction projects?