Update to my previous issues.
I went through a series of trial and error steps, using suggestions made my many sources and I man (knock on wood) have gotten my wife's iPhone4 to keep connected to wifi. I tried everything from router settings, to reset all connections, to disabling data and reconnecting... none of them worked.... i just created a new network connection (named the same as the one I was unable to connect to) and so far it seems to stay connected.
Since the new setup, the wifi stayed conencted through resets and hard shutdowns, but have not yet had the chance to leave signal and come back to see if it automatically detects and reconnects. That is tonight's task. Fingers crossed that this problem is now behind me (and my wife)