I've stayed overnight but not too often due to truck noise/activity. Perfer Walmart like others have mentioned. I've found that most Walmarts are OK to stay at overnight unless there are city codes against it. My choice for overnights is Cabelas, I've always had good luck at every single one even if there are city laws that are supposed to prevent it. Good example was in Anchorage, the Walmarts and Fred Meyers there didn't allow overnight stays but even though there were signs put up a tow company at every place in town, including Cabelas, there were probably 10-15 RV's there overnight. Every one I've stayed at had a dump station too, coin operated I think $5 or so, and they have designated RV parking areas. SUPER RV friendly. Many casinos also allow overnight and since they are on Indian land usually they aren't necessarily subject to city laws. Also check
http://freecampsites.net for real folks input on places, it's helped me out several times in tought spots.