Honestly seems like it was a blast, I've seen hundreds of pictures from the event and all of the models look like they're having the time of their lives despite it allegedly being blisteringly hot (and the sun really is intense in a lot of the pictures).
It was well attended as you can see throngs of people in backgrounds and it seems like each group of girls was posted up rather close to each other so maybe there was just a lot of energy to go around? Also, this was at Tokyo Summerland like last year's Enako/Muse session, and I think the amusement park vibe kind of gives these photos a real "summer fun" air compared to like Shirobakoto Waterpark where it looks kind of desolate with the place rented out (lots of photos come to mind featuring empty pools and nothing but concrete; my favorite pictures from that venue always feature the large slide in the background).