Yes, 2-2.5 hrs. at HND should be more than enough. JAL indicates 70 min. for from domestic to international transfer at HND. Unless there is a long line at departure passport control at Terminal 3, 70 min. should be more than enough time.

Transfer question
 

Should be an easy one but I'm dense.

Flying into HND arriving just before midnight on one ticket Have a noon the following day, so about 12 hours, flight out of NRT on a separate ticket.

I'm just there to do some quick duty free shopping at the airport for my wife (and I love flying) and want to know the best way to get to NRT after arrival at HND.

Would you immediately travel to NRT and stay close to there, or stay at like the terminal 3 hotel at HND and go to NRT early morning?

Also, what's the easiest way to get from HND to NRT at around 7am?

There will be no public transportation from HND to NRT at the time of your arrival. If you want to get from HND to NRT around the midnight then only option will be taxi or driving on your own.

I think the best option is to stay at HND and go to NRT in the morning. The best option will be Limousine Bus, which depart right form the terminal and arrive at the front of the terminal. Morning schedule of Limousine Bus from HND Terminal3 to NRT is:

6:40 a.m. (arrive at NRT 8:00 a.m.)
7:40 a.m. (arrive at NRT 9:00 a.m.)
8:25 a.m. (arrive at NRT 9:55 a.m.)
9:00 a.m. (arrive at NRT 10:30 a.m.)

Thank you AlwaysAisle

Is it preferable to purchase the ticket in advance or can it be purchased on arrival?

I don't know about purchasing the ticket around the midnight. It is possible that bus ticket counter with agents will be closed at midnight. There are bus ticket machines, but if all Limousine Bus service of the day is finished, then it is possible that the bus ticket machines are turned off around midnight.

During any other time of the day, yes, you can purchase the ticket for Limousine Bus. But I never tried around midnight, and I do not know if you can buy tickets for Limousine Bus around midnight at HND Terminal 3.

You can book and pay online

https://webservice.limousinebus.co.jp/web/en/

Thank you. If I do pay in person, does the transaction have to be in cash, or do they take credit cards at the kiosks?

Major credit cards are accepted at the kiosks.
https://webservice.limousinebus.co.jp/web/en/Top.aspx

I would suggest reserving your ticket in advance for peace of mind, Someone recently posted that they got the last available seat on a bus out of HND, and they watched the desperate folks who were left behind snatching at the skids of the Huey as their transport left the area. Stressful stuff.

Narita layover
 

I have an 11 hour layover in Narita. My flight arrives at 7 am and takes off at 6pm. I'd like to leave the airport and sightsee in Narita for the day. Is taking the train in from the airport the easiest way? It looks like I have lots of choices of things to see. This is in early February on JAL if this makes any difference. Thanks!

For downtown Narita, take a Keisei Line local train to Keisei Narita station. From there, you can walk to the temple (about 15 minutes walk). If you want to continue to the Aeon mall, it's another 20 minutes or so on foot. You can return by bus.
You might also be interested in visiting the Aeronautical museum and "Yamato no Yu" onsen. Those are not in downtown Narita. They're on the south side of the airport. To reach them, take the bus for the museum from the airport terminals.
Bus and train fares will be a little over 200 yen for each ride. You can buy individual tickets with cash or download the SUICA app to a mobile phone and charge it with a credit card (see separate thread for mobile SUICA).

Arriving at NRT at 7:40pm and my hotel is close to Keikyu Kamata
 

We will be arriving in T1 on Christmas day (25th). I think my hotel doesn't have anyone checking in been 1am o 6 am.

Is there a chance that we can be there before 1am?

The hotel is Oriental express Kamata hotel.

Thanks!

That should not be an issue. I can't imagine that Narita arrivals are particularly busy that time of day, as arrivals will have ramped down. You need about 1.5 hours or so on the train to get from Narita to Kamata Keikyu, maybe a bit more that time of day, as there are fewer express trains. Seems your last train option is 22:43 from Narita arriving 00:11 at Keikyu Kamata.

From what I saw there will be like 10 flights coming in and ET and BR are possibly wide body aircrafts.

Someone on Reddit wrote that there was a 3h wait at the immigration at T2 at around 7pm. I hope that's not the case.

Bit of a dilemma.

Overnighting at one of the airport hotels near Nartita would be a good option for flights arriving in the evening. Transport from Narita to Tokyo isn't easy in the best of situations. IRROPS are a real thing. A taxi from the airport would be the best option in the evening, but very expensive. Arriving after 8PM risk no-show cancellation.

It is easier to stay close to Narita but we have a 9am flight from hnd. That's why I prefer taking the journey on the same day.