Incheon to Daejeon
When you arrive @ Incheon airport there are buses that goes to Daejeon straight.
Look for airport limousine service in the airport and ask for Bus to Daejeon.
It costs around 13000 won (9Euro) and price differ depends on type of bus.
It takes 3 hours from Incheon to Daejeon and there are 3 stops. Hotels are usually around Yuseong area and government complex area. However taking taxi in Korea is easy and cheap. As long as you have written address (preferably in Korean) you will be saved
Seoul to Daejoen
However coming by train will be most convenient. I would recommend to take KTX train from Seoul station. This would take only one hour to reach Daejeon station. Plus from Daejeon station to our marriage place is not so far.
Cost of KTX is 32100 won (21euro) one way. If you like to save money, you could also take slow train. It takes 2 hours to reach Daejeon station and cost 10500 won (7 euro). If you like to book train ticket in advance, you can check http://info.korail.com/2007/eng/eng_index.jsp
From Daejeon station to wedding place, you can take taxi.
대전광역시 동구 판암 2동 529번지
I would recommend to print address in Korean and show to taxi driver.