In Ueno, Ichiran (tonkotsu ramen) is along the west side of the JR station and is open 24hr.
Sushitsune (inside JR Station / Atre complex) is a very solid sushi place at reasonable price.
Problem with Ueno, though, is there doesn't seem to be any decent hotel. If there is one that I don't know about, then I'd like to know.
Did a quick search. The only Ueno hotel rated >4 on rakuten that's not a clearcut business hotel is this one: www.cocogrand.co.jp/uenoshinobazu Seems like an okay place.