The distance from Seoul to Busan is approximately 335 kilometers. The easiest and most comfortable way to reach Gyeongju from Seoul is by using the Korean Train Express (KTX), equipped with various facilities such as modern bathrooms, vending machines, and comfortable seats. KTX is available from Seoul Station every 2 to 2.5 hours. You can purchase KTX tickets for around 71,297 KRW.

For your itinerary in Gyeongju, start your morning by visiting Shilla Millennium Park, a historical theme park where you'll be served by staff wearing hanbok. Alternatively, you can visit the Tomb of General Kim Yusin, where along the way to the tomb, you can see cherry blossoms blooming in spring. You will also encounter 24 stone foundations with 12 statues guarding his burial site.

Continue your sightseeing journey by visiting Seokguram Grotto, one of UNESCO's World Heritage sites and the 24th National Treasure of Korea. In this stone cave monastery, you can find the Buddha statue referred to as the "Silla people’s smile." You can also explore other places like Poseokjeong Pavilion, the villa of the Silla dynasty, although now only a shell-shaped stone waterway remains, located on a stone beside a river in Gyeongsanbuk-do.

To spend your afternoon until evening, take a stroll along Hwangnidan Street, filled with a new retro atmosphere. Here, you can shop at various stores and capture beautiful photos at cafes, restaurants, antique shops, photo studios, and traditional beer pubs lining the street.

When visiting Gyeongju, make sure to visit the Gyeongju National Museum, brimming with numerous relics from the Shilla era. Various attractions here include the Hall of Shilla Art, the Hall of Shilla History, the outdoor exhibition hall, and Wolji Hall. You can see valuable displayed items such as golden crowns, Buddha statues, the Bell of King Seongdok, and the three-story stone pagoda of Goseonsa.

Gyeongju offers an endless array of cultural and historical attractions to explore, such as the Yangdong Folk Village, which was designated a UNESCO World Heritage Site. This village holds traditional value in its architectural style. Taking a leisurely stroll here during the morning or evening is highly recommended.

You’re also highly recommended to visit the Cheomseongdae Observatory, one of the oldest astronomical observatories in Asia used for weather prediction. You can explore this observatory during the night to witness the moonlit sky filled with stars.

If you are looking to indulge in sweet treats in Gyeongju, Hwangnam-ppang is a must-try dish. These small cakes are filled with sugary red bean curd, making them a perfect snack to enjoy while on the go.

For a heartier and soupy option, consider trying Sundubu jjigae, a type of traditional Korean stew. It features soft and silky tofu with delicious beef or seafood. Additionally, explore Chueo-tang, made from pond loach fish broth boiled with various soybean pastes, chili pastes, assorted boiled vegetables, ginger slices, and green beans.

You can also sample pajeon, a Korean pancake variation with green onions as its main ingredient. This snack is suitable for enjoying as an appetizer by eating it with rice, soy sauce, and vinegar.

If you plan to visit Gyeongju, the best time is from March to May or September to November when the weather is favorable. It is advisable to avoid the late June to early August period as it often experiences typhoons during that time.