[JRTJH]

Have you considered pulling the plastic trim ring from around the roof vents? They are usually held in place by 4 screws. Remove the screws and pull the trim ring down, it will give you access to the "attic space". Use a "strong string tied to a mouse trap" to secure the trap so an active mouse can't pull the trap deeper into the attic space, and set a mouse trap or two around each roof vent. Hopefully you can catch and remove the mice.

You don't want to just slip a trap up there. If you happen to catch a mouse "by the foot or by the tail" and it drags the trap into the middle of the attic, you'll NEVER get rid of the "rotting mouse smell" and you'll have to pull "half the ceiling down" to get to the trap.... So, anchor them to the area round the roof vent !!!!!