I've been on a delayed UA72 and we were eating breakfast at 1PM, which I didn't mind at all. In fact, I wish all meals were breakfast. Mmmm.
My friend is on the same flight as you today (6/1), and he's been told to report as if the flight is on time.
I can't imagine being at the airport doing nothing for 5 hours, so I'm going to try and get a gate pass so I can host him into the lounge. If they deny me a gate pass I'm buying a fully refundable HA inter-island ticket, which I think will still cost me a $25 refund processing fee.