We're planning to go to Tobe Zoo on the second day of our vacation.
We're hoping to go to Tobe Zoo on day two of our family vacation.
この場合、次のように言えますよ。ーWe're planning to go to Tobe Zoo on the second day of our vacation.「旅行２日目はとべ動物園に行く予定です」on the second day で「２日目」を表現できます。ーWe're hoping to go to Tobe Zoo on day two of our family vacation.「家族旅行２日目はとべ動物園に行けたらと思っています」on day two でも「２日目」を表現できますよ。ご参考まで！
カナダ 
