Would definitely stay at the hotel again, but I would bring my own food for breakfast and arrange for more sleeping space. Booked room for 1 adult and 1 child (11 years old) but bed was only a double. It was very tight but we made it work and enjoyed our visit in Karatsu very much. Definitely plan to go to some of the beaches, Karatsu Castle, and Takatori home. We also went to an ancient history museum that my son enjoyed. All are within 20-30min walking. Train to other locations is relatively convenient as long as you are adventurous.