It's good you solved your problem. For others interested, I have 3 usb cables and 2 plug in adapters (the extras were maybe $5 off ebay). I really only use the cradle for the audio out to sync to my tv (for synced podcast commentaries).
I have a cable plugged into the wall in my bedroom for nighttime charging (it's my alarm clock), I have a cable at work hooked to my computer for charging during the day (if needed), and a cable at my home computer for syncing. I don't use the cradle at any of these locations, because of the case I have my iphone in.
The only time I use airplane mode (except on an airplane) is when we're syncing audio on the tv. We get a buzz in the speakers otherwise. I turn off wi-fi in the car, because it seems to interfere with the bluetooth connection of the car. Otherwise, with multiple charging options, it doesn't seem to run down that fast.
Oh, and the extra plug in adapter is in the living room, where I charge the phone when I'm watching videos from the iphone on the tv.
I'm starting to think this phone has taken over my life...