John: thank you.
I have tried all of these, except for hard wiring the expresses, and iStumbler tells me there are a lot of networks in my city neighborhood. I suspect interference is the issue and I won't be able to make it work and can't go to Apple TV or use AirPlay for music. I was hoping there was an app that could evaluate my network and tell me what settings/configurations would make AirPlay work or tell me it can't be done.
I have 2 airport express and an AirPort Extreme (all 3 less than 2 years old and most up-to-date firmware) and they are near each other (first express is 10 ft away up one floor, the next is on the same floor and 15 ft away). I have changed channels, left at auto settings, tried 5ghz and 2.4ghz, turned on/off guest networks, extended/joined networks, moved things, etc. I have served music from my 3 year old iMac (hard wired to the extreme and wirelessly) and served up music from iPad and iPhones wirelessly. Same results.
The house is very old and running wire is not an option. That was the promise of wireless. I have tried a bridge that runs through the house electrical system. Unfortunately, being an old house, the electrical system option didn't work because throughput dropped significantly.