Very detailed and well written. It sounds like you've hit on everything I would mention.
Can you really not do better than 2750 rpm @ 65mph? If so that kind stinks, but it still sounds better than your current configuration.
Are there any models of this car or similar cars with better EPA ratings? If so my advice would be just to steal as much as you can from that car,
. That's pretty much what I've done, but then Hondas are likely more interchangeable than toyotas.
Looking forward to your progress!