Background info:

I'm replacing the termite-infested soffit and rake board on an early 60's California ranch-style home.

The rake board on the gable is only attached to the roof sheathing by nails that go through the roof sheathing, through the fascia boards and into the rake board. There is a piece of trim board (not visible in the photo) that covers the ends of the soffit boards which has the drip edge from the roof over it . There is no fascia attached to the rafters. There are no purlins extending from the last last rafter which is flush with the side of the house.

Q: When I install the new soffit and rake board, how do I attach the new rake board without hammering or drilling down through the plywood roof sheathing?

I can't drill or hammer up from the bottom through the rake and soffit boards into the roof sheathing because then I will probably poke holes through the sheathing and asphalt shingles.

Do I attach false purlins or soffit brackets to the last rafter and secure the rake board to those?