This place will offer everything that you need. Especially having a kitchen available is great and restaurants such as Pizza Hut and Korean buffet are just next door. The location is great: 5 mins to the subway station on foot. The subway takes you directly to the airport within 10 mins and to Seoul city center within 30 mins.
No language barriers here since the owners who run the guesthouse speak fluent English, Russian and of course Korean. Even communication in Spanish is possible.