Gyeongsang is the large southeastern part of Korea, and Korea Trip Map currently covers two places in it: Busan and Gyeongju. They make a satisfying pair because they offer opposite experiences. Busan is Korea's second-largest city, a port with beaches, steep hillside neighborhoods, fish markets, temples on the sea cliffs and a subway that makes it easy to get around. Gyeongju is a small, flat city that was the capital of the Silla kingdom for nearly a thousand years, with grassy royal tombs, an ancient observatory, a lantern-lit pond and mountain temples.
Both are reachable from Seoul by fast train. Busan is roughly two and a half hours away. For Gyeongju, the KTX stops at Singyeongju Station, roughly two hours from Seoul, with a short bus or taxi ride into the historic center. Between the two cities, buses and trains take about an hour or a little more, depending on which you choose. This makes it practical to combine them in a single trip, spending a night in Gyeongju and two in Busan.
Our advice is to treat the two as different moods. In Gyeongju, plan to walk, rent a bicycle, and see the tomb park and pond at dusk. In Busan, plan around the coast, markets and neighborhoods, and leave time for transit between areas, since the city is long and hilly. Other Gyeongsang cities are not yet on this site. Hours, fares and conditions change, so check them before you travel.