Was it ever mentioned when she went to the store?
That store always has a few cars in front of it when I have driven by. All the store people know the locals. There are benches and tables out in front where some people hang out. Granted, it was the 4th of July, but I would guess that if something happened in the small lot SOMEONE would have seen something...
Given Ruch's size (less than 1000 people) I would imagine that news like this would travel fast and anything strange would have been reported on.
BBM This article said her boyfriend was the last to see her at around 5pm at the store:
http://www.kdrv.com/jacksonville-woman-disappears-july-4th/