This state park is just west of Onteo Beach and is accessed by the Lake Ontario State Parkway.
The park has a supervised beach area, picnic tables with grill-stands for cooking (you bring you own charcoal), pavilions open and pavilions enclosed, three playgrounds (one at each major parking area), nature trails for hiking, birding and biking (and trail-skiing in winter). There is a small boat launch area for canoes and kayaks and areas designated for fishing (both summer and winter). The park includes a campground with 164 tent and trailer sites, concession stand, camp store, community building and restrooms at each circle of campsites.
A food concession and ice cream shop are at the west end of the park.
There are panoramic views of the lake from most of the picnic sites.
And it only costs $5 per car for parking all day. Camping fees are extra.
See website below for rules and access times.