On a recent road trip, we decided to have a picnic lunch in Lake Geneva. Spotting this park on the map, we figured this might be the perfect place.
The biggest surprise is that if you try to drive into the park, you will need to get a vehicle permit. (Wisconsin DNR's rules) The lady at the booth told us the (out of state) permit was $11 for the day. When I mentioned that this seemed high for what would probably be a 60 minute visit, she said there were some great trails and the picnic area and playground are both very nice.
In reality, there weren't *that* many picnic tables, although there was one covered shelter house. The playground was smaller and older than you'd find in most small town city parks.
We did walk on a couple of the trails -- again, they were OK, but nothing special. I would agree with the others about the beach: it's quite narrow, and has a somewhat busy county road right behind it. I wouldn't recommend it for younger children.
Tip: Try to find a free spot to park nearby, to avoid the admission fee. Also, we found out later that some Wisconsin parks offer a one-hour sticker, which is about 1/2 the price of what we paid for our daily sticker. (This was never offered to us at the gate, so might not be available here.)