I really like this arc. It's definitely strengthened their relationship, and we've learned a lot more about both of them. Kureha isn't just some happy-go-lucky senpai who lives for teasing and flirting; she has real depth. There are moments where she's genuinely brooding. Even though the whole objective was to run away, she's been actively processing why her father treats her the way he does and how she might make amends with him. That gives her way more layers than we initially gave her credit for.
Then there's Takashi. Usually the timid, reserved one in the dynamic, but on this trip he's been surprisingly aggressive. I think that's coming from just how much stronger his feelings for Kureha are than we first realized. Maybe it's the threat of her being forced back home that pushed him over the edge. Either way, it worked out because at the start of the arc, Kureha was dead set on figuring everything out on her own. However, I think Takashi's assertiveness made her want to rely on him, to the point where she started opening up a little bit about her relationship with Kotaro.
As for what Kureha figured out, since they were on the topic, I'm leaning towards "male desire." Kotaro when we first saw him made it a point that Kureha and Takashi maintain an appropriate relationship for that of students. So I'm guessing the reason he became a nagging and controlling father is because he didn't want his daughter to be taken advantage of by some dude(s). It might even tie back to his wife being similar to Kureha. A "Madonna" type at their university with guys lusting over her. But Kotaro, like Takashi, was "different" and treated her with respect. However, having seen firsthand what university guys are like, he started being overprotective but it just came across as controlling and a lack of trust in Kureha to make rational decisions.
Thanks for the translation!