It's been a couple of years since I've done this but there is, or there was, an AA flight JFK-SEA on a 737. This has two advantages: coast-to-coast direct is long enough to qualify for the same level of TPs as a transatlantic sector, and as a two-class aircraft, if you book J you sit in, and receive TPs for, F. I have in the past made silver in a single trip using this routing. The only down side is it's AA's domestic F which is just 2+2 seats not any kind of bed, but as I always flew it in the daytime it never bothered me. If this flight is still available, working it into your itinerary is about the most lucrative way I know to get to the west coast.