hanezu

Sumida River (the bridge)
Herb garden travel diary Katsunuma Garden ('date' in episode 2)
Chikurintei mizuho Hatago kikori (the inn in episode 3)
KKR Port Hill Yokohama (episode 1 and 5)

You can find more here with the locations: https://damako42.com/koiwosurunaranidomegajoto-roke#toc1

They're 20 and 30 respectively, according to the official page https://www.asahi.co.jp/sugardoglife/chart/

The “more than friends and less than lovers” thing is in the synopsis of another upcoming BL “I Hear the Sunspot”, not this one.

They do have an intimacy coordinator on set.

https://www.tv-tokyo.co.jp/plus/drama/entry/202406/15228.html

I’m genuinely baffled by the people who are still questioning Takashi’s sincerity after EP4..