The hotel address decides the bus case
Myeongdong is an area, not one stop. Compare the live airport-bus stop with the exact accommodation entrance, including hills, crossings and the final walk. A bus that looks slower on a timetable can be simpler than rail when it removes a station change with luggage.
AREX still needs a final leg
The AREX Express terminates at Seoul Station. From there, Myeongdong usually requires another subway, taxi or walk decision. Count platform access and luggage movement instead of comparing only the airport-to-Seoul Station segment.
Late arrival changes viability
Immigration and baggage collection happen before the transfer starts. For a late flight, check the same-day operating window after allowing that buffer. When normal services no longer fit, compare an official night route with a metered taxi rather than relying on an old blog timetable.