It is definitely in Gig Harbor, and Tacoma and much of the South Sound. I don't think it is prevalent in Clallam County on the Peninsula---- yet.
If your neighbor has old run down 'veteran' trees you have a headache on your hands. Try to convince them to cut them down. Also, I think that summer apples provide a great population explosion for the later fruit so I'd eliminate the likes of 'transparent'. Learn also about the alternate hosts of the apple maggot, "unfortunately, there are a lot of them". I would cut down any hawthornes along the fence row, and I think Snowberry is another host plant.
Some folks put a nylon boot on each apple, but for a larger grower this is not realistic or practical.
Do practice good hygene in the growing season and remove all windfalls as soon as they hit the ground.
Probably best to bury them a few inches down in the soil--- too deep for the larvae to emerge. Failing in that I'd suggest putting them in a plastic bag and sealing the fruit so the adults cannot emerge at the landfill later.
I think a campaign to eliminate the pioneer fruit trees would help, unless they are well cared for. Nothing against having them, 'if you're taking good care of them".
I think the epidemic of apple maggot problem outweighs the nostalgia of saving every old 'vintage' tree.
From what I've seen locally, the Apple Maggot likes the same sorts of apples that the Codling Moth favors, ie fragrant ones, like King and Caville Blanc, and Hawaii.