Based on where Mr. Liao has taken Xiaodan on a holiday, it is the Cameron Highlands in Malaysia.
It turns out Hongsheng was being transferred to another place of work by Haowen after the latter found out Hongsheng was given a job offer at Sai Wei's jewellery shop, after Hongsheng met up with Sai Wei after work and told him how his day went.
After Sai Wei openly declared of wooing his second cousin Mingzhu in Ep 18 (1995), he began following her around after spotting her at the hospital visiting Renniang, even to a restaurant at one time before she left in a huff.
The song performed at the resort where Mr. Liao has taken Xiaodan to is Engelbert Humperdinck's Spanish Eyes.
Renniang is still recovering from the kidney transplant operation in Ep 18 (1995), as shown by Mingzhu visiting him at the hospital at the beginning of the episode, until his discharge later in the same episode.