The train service is very good but if you plan to go to a downtown hotel, it might be better to use a bus as they stop at various hotels and there is less luggage lugging.

There are "Jumbo" taxis that could take 3 plus luggage - about 80 USD each way plus bridge toll.

The "airport" hotels are fine, but there is really nothing else in the area at all.

Perhaps try the Seoul Garden hotel - the first stop from the airport - http://www.tripadvisor.co.uk/Hotel_R...tel-Seoul.html.

The KAL bus (called limousine) stops right outside and is more comfortable than a taxi.