Kamp Siesta is an establish campground in shade trees located adjacent to the fairgrounds and city park. The park is very nice and suitable for walking or biking and is on a bluff that overlooks the  Neosho River. The park includes a swimming pool, tennis courts, pavilions, and playgrounds. Amenities such as gas stations, hardware store, restaurants and groceries are all with a mile or two of the campground and well separated from them by quite neighborhoods.  While there is not a lot to do in Oswego itself, it is close to strip pits east of town  left over from coal mining that are good for fishing and there is a nice 9 hole golf course just west of town. There is also fishing down on the river. This river is known for it's large catfish.   The park is easy to access from the highway and plenty of room to maneuver larger rigs. I grew up in this area and know it well. The campground is quiet and well patrolled and at $10 a night it a cheap but relaxing place to stop and unwind. 

I believe it is open year round.