Faction camps require 1 or more friendly NPCs to work as labor. Currently, the implementation has a single fixed upgrade path for the central camp, 4 expansions options, and some fortifications.
Faction camps don’t interact with zones much (yet): NPCs can sort your loot for you, which is nice, and they use the same loot zones as you do, which is nicer and a recent change from a less satisfactory system. At some point I’m going to revamp the camp farming system to use farming zones.
There is active work ongoing to make faction camps more flexible. All the effort is still going on behind the scenes, but visible changes should start becoming apparent soon. I mean, beyond the bit where you can use two-way radios to talk to distant NPCs.