The restaurant Riccardo that often appears in the drama is also in Heyri Art Village (also is the place where Se Joo and Jeon Seol had their date), but this place is closer to gate 1 of the village, you can find the place following the map on their website, the restaurant is marked with the green dot on the map.
Blog of this restaurant (with menu and pics of the restaurant)
餐廳內部可以看這個 What it looks like inside the restaurant
Hapjeong Station Exit 1. Take Bus No. 2200 and get off at Heyri No. 1 Gate Bus Stop, that should be closest to the restaurant.
If you are going to this place, you can go to Forest of Wisdom that is also in Paju on the same day.
韓文名 Name in Korean：컴프트리 레스토랑
地址 Address：경기 파주시 탄현면 헤이리마을길 37-31
當你沉睡時Ep1/2丁檢遇到女主和男二的這停車場, 左邊那家餐廳就是COMF-Tree 餐廳，大家下次去記得去這餐廳後面的停車場看看。不知是不是晚上都會有這麼美的燈飾？
The car park in While You Were Sleeping Ep 1/2, COMF-Tree Restaurant is the one on the left hand side of the pic, when you go to this place the next time, remember to go to the back to see the car park. Dunno if these pretty lights are there every night??