soffit to attic access on gable end?
Because you're on a gable end hit wall sheathing and sheathing on the gable end truss, depending on height. You'll want to try and drill through the sheathing as high as possible to get above the wall plates and truss bottom chord. You can drill through the truss if necessary.

Your best bet might be to route the cable around to the overhead door wall, where you'll find open bays between the trusses. There may be insulation baffles, but you'll have a relatively clear route.