I don't know if the time was on the receipt, but based on this interview
http://www.localnews8.com/news/3-mo...=social&utm_source=facebook_KIFI_Local_News_8 the sheriff states the time was around 10:30/11:00am that they went to Leadore. The article states the cashier and receipt prove the trip there. Since the sheriff gave a roundabout time, I gather even if there is no time on the receipt the cashier was able to give a good estimated timeframe - or it was realized by other means during the 3 previous months such as going through previous receipts from that register to gain a good approximation of time.
As far as DeOrr being with them . . . there's no confirmation of it, but if the parents said he was with them, then I think that may put all 3 of them in that 4 hour window?