Frequent train connections between the Geneva airport and Lausanne exist.
EPFL is located between the communes of Lausanne and Ecublens and can be reached by m1, the metro line connecting Lausanne-Flon and Renens stations (Official website of public transport of Lausanne - in French only). EPFL is easily accessible by public transport from most parts of Lausanne and its environs. You can find the route from any address in Switzerland to EPFL on the web page of the Swiss Federal Railways.
You can find a list of hotels in Lausanne on the official site of Lausanne city by clicking here.