>>95909912
Have you considered that you could just as easily make one of the PCs the Lord-Commander?

Here's how I'd play it if I wanted to do something like that:
>Alright lads you're members of a loose organization that guards what's left of a Hadrians Wall-esq fortification originally built to keep out the orc menace
>Here's a map of the area, I want you to pick what part of it is your personal responsibility, 3-4 hexes should do, quieter areas are expected to scout and try to keep down their numbers, breaches get additional troops sent to them by the 11 Kingdoms and those ones with little skulls are lost outposts, if you can reclaim one of those then you're going to pull some real attention and accolades. The responsibility is loose and you're expected to make your own judgement-calls and fund yourselves to an extent.
>Those areas with an outline and banner over them are the currently held parts of the wall, you might notice it's about 25%. Orc incursions are common to the south as well and beyond the wall is savage lands
>One of you is, on paper at least, the Commander, but all that means is that you can claim right of hospitality for yourself and one horse each and even that is spotty these days
>Oh and the Wall itself in an ancient thing of magic built by bullshit Warlock-Rome, the inside has passages and so on, no one has mapped those in a thousand years
https://www.youtube.com/watch?v=AjUmULa0R-8

Wall is an immediate Mega-dungeon, players have a general overarching goal and map of the areas closest to it, it'll be their choice to strike out or try to play faction politics with the other commanders, locals, ect. You can have ruined villages, fortified border towns, ect.

Put the control in the hands of the players. I know it's hard to do that when you're used to running a story rather than a game, but trust me, it'll work.
Oh as for hostages, ect, as slaves from ACKS for saved innocents (aka: ~50GP)