If you're in Affaires, you have access to the arrival lounge in 2C. That is open until 14:00 (2 p.m.) but that still leaves a very long wait until your flight to BKK. If the Sheraton is too pricey, there are a few cheaper hotels like the Ibis and the Novotel that are at the bus/RER station (for connections into the city). ADP shuttles run every 5-10 minutes from CDG2 and rates for a room should be more like 70-100 Euros. By the way, there are two Ibis hotels near CDG so make sure you get the right one.