What you need are "zoning laws", with parcels of land requiring a certain amount of riches or influence to be sent up the chain to the Mountainhomes. Now, obviously, a "homesteading initiative" drew these villagers out here in the first place, so each of the seven "freeholders" would be given a parcel of land (or two parcels for the expedition leader), to divide as they see fit. 1x1 embarks are 48x48 squares (2,304 total), so you can easily find out how many squares of land exist on the map by multiplying the number of embark squares by 2,304. This would also give you guys an idea about having a basic economy, because the ability to use "squares of land" could be bought and sold in-forum for relative riches. (Which is basically what the feudal economy was founded on anyway, so this works in-theme too.) Rights to the use of land would of course be more or less worthy if they've been "improved" or are still just vacant lots, so the ownership of some land would be "worth more" than the ownership of other ones. After all, rent is just buying a limited use of a specific size of property, so each "plot" of land might have to have it's "use-rights" bought before it could be used - first from the Mountainhome via caravan tribute (offered as a gift to the caravan) and later from land-owners who have bought use-rights. That would keep the "sprawl" from happening too quickly - not until somedwarf or other was able to create enough of a surplus to buy more parcels from the Mountainhome or had goods they could trade "in rent" to some other land-owner to buy use-rights to other parcels of land.