I tweaked a couple of my vanilla player houses, hanging up items on the walls etc.
Using "Don't havok settle" and the script "defaultdisablehavokonload".

Seemed to work fine upon re-entering the house, but after returning to the house after some time away, several of the items had fallen down, some only slid half way down the walls.
They're still immovable, just out of place.
I'm not using an obscene amount of scripts or anything.

Any insight would be most appreciated!

Have you set the properties for every object that have this script ? Everything on false (unchecked).

Looking at this script, the problem can be that havok run and move the object before the script run. Once one object is simmed, a lot of object near it can be simmed and you have a chain reaction, everything falls before the script can change anything.

EVENT onCellAttach()    if (beenSimmed == FALSE && Self.Is3DLoaded())        setMotionType(Motion_Keyframed, TRUE);         ;debug.trace("havok disabled on: " + self)    endifendEVENT

You should look if this part of the script is executed for your objects.

Thanks for the response, I'm not as well versed in these things as I'd like, but I'll dig in to the bowels of the thing and see what I find.