I have used the airfield on several occasions, there is a hotel fairly close, but I (personally) wouldn't fancy walking to the station as it is about half an hour away on foot. Trains to Paris run frequently and the journey takes about 20 mins. It is possible to request customs, so obviously if you do this you don't need to clear elsewhere - you will also have to clear customs outbound, so again you'll have to request it.
I have always found it a freindly place, and despite filling in the landing details form I've never been sent an invoice. An alternative worth considering (Unless you are going for Eurodisney) would be Pontoise, although the taxi to the station will cost you about 130FF.
Have fun