My fiancee lives in the Smyrna area and wanted to go out to get some sun. Rather than driving to the beach, we decided to go to Killens Pond State Park.
Upon arriving, we were disappointed that boat rentals were not available until later in the year. However, we experienced the same problem at Lums Pond State Park and should have remembered. Instead of moping or driving elsewhere, we decided to go fishing off the campground pier. I'm squeamish about hurting any animal so I just had fun casting into the pond. However, my fiancee caught what appears to be a small, large-mouth bass. Of course, we through him back in the water. We enjoy fishing and spent about three to four hours on the pier lounging and fishing.
The entire time we were there, walking a few trails and searching for the campground pier, we never saw a Park employee.
We have an annual pass to the State Park ($27) but if you're just visiting once, entry costs $3 for cars with Delaware Plates and $6 for cars with plates from other states. The campground features very nice cabins that can be reserved at the Delaware State Park website. My fiancee stayed in these cabins with family on several vacations when she was younger. In the summer, there is a small water park which is three water slides and a pool. During the season (I believe after Memorial Day), you can rent row boats, canoes, kayaks, or paddle boats at reasonable rates per hour or per day. However, I've heard that Killens Pond gets very busy during the summer with camping and visitors.
Overall, camping and visiting Killens Pond is always a fun, relaxing time but I would go before peak-season.