I like that outposts are being expanded upon, but I think more can be done. I think some if not all outposts should have a mod slot that can use some new mods made just for outposts. Some outposts can even use unique mods that can only be use on specific types of outposts. Additionally all the mods can have a 1 time or continuous upkeep, depending on what it does. Some examples I have in mind are-
Car parking mod: Allows you to park a car at an outpost with this mod and freely move items into and out of its inventory from your base and from any other outpost.-- it can have a 1 time upkeep cost of materials labor and parts.
Sleeping hammocks mod: usable only on bed outposts. It decreases the total beds provided, but provides a bonus to happiness. I could also see characters with certain traits receiving an extra happiness bonue from them.-- it can have a 1 time cost of labor then a continuous cost of parts to maintain otherwise the happiness bonus is removed and the bed count stays the same.
Encampment mod: usable only on bed outposts. Increases number of beds provided, but decreases happiness. I can see it having a similar connection with some traits just like the hammock mod.-- it can have a 1 time cost of labor and parts then a continuous cost of parts to maintain or the extra beds is removed while the decreases happiness remains.
Sound system mod: can be used to increase/decrease base noise levels. Can also be used like a distraction tool to draw in the surrounding zombies.-- it can have a 1 time cost of labor and some of your distraction tools then an extra cost when you use one of its actions.
Landmines mod: just like in SOD1 they will increase your outpsost's range slightly but not as effectively as before. Since this was OP in SOD1 I can see this mod getting a nerf alongside my idea for the potential cost. One nerf I can see being done is that it can only kill a limited number of zombies before the effect deactivates, and special zombies killed by it will not count towards missions and plague zombies won't drop samples.-- it can have a 1 time cost of labor, parts, and some of your store explosives then it can have a repeating cost of some of your store explosives every time you use the arm mines action.
Keep in mind the mods I listed are just suggestions, and do not have to be the actual mods created nor the only ones. I shared them just to give examples and to possibly spark more ideas. Thanks for viewing my idea!