You will have more than 5 hours, it doesn't take 3 hours to clear and re-check, even if you are switching terminals. But if you are going to standby for the 4:30pm flight, that changes things.

I'd suggest the Japan National History Museum in Sakura. Take the Keisei Limited Express to Sakura (about 20 minutes) and follow the signs (in English as well as Japanese). You can eat lunch at either the cafe at the museum or at a place near the train station. Note that the museum is closed most Mondays.

Do not take the JR airport-Narita train to Sakura, it is a much longer walk to the museum from the JR station and is not at all signposted.