2nd Day: "Todaimae" (Namboku line, Tokyo Metro) is the nearest station to the Hongo Campus. This is a map of the metro stations that are in the Campus area.
If you stay in Japan only to attend ELiTES meeting, you’d better reserve a hotel in the center of Tokyo, because the conference sites are there. Kashiwa is far (it takes about one hour at least from Kashiwa campus to ELiTES conference sites).
The website of KAGRA f2f meeting shows some hotels near Hongo campus: http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Meeting/F2F
Kashiwa campus: rooms in the guest house are very busy. In almost all cases, you must stay in a hotel outside in the weekends, even if you can stay in the guesthouse in weekdays.
If you want to reserve a hotel near the Kashiwa Campus or just to see the map, visit this link. There is also a new hotel near Kashiwa-no-Ha campus station, which is the nearest station to Kashiwa campus. It takes 10 minutes on foot from Kashiwa-no-Ha campus station to the hotel. The bus to Kashiwa campus departs from Kashiwa-no-Ha campus station every 10 minutes or 20 minutes.
There are not many restaurants and shops around this hotel, but there is a convenient store near it, open 24/7.
Some useful information if you are going to reserve a hotel near Kashiwa station:
If you need any helps, please contact the University of Tokyo secretary office: firstname.lastname@example.org