Does it cost to use a picnic table and do they have grills? Also does it cost to swim at the beach area?

No cost for anything

The regular picnic tables are free but if you're referring to the picnic tables with seating and a grill that have letters labeled on them (kinda like shelter areas) you must reserve those. All other open area picnic tables are free. The ones that are on decks with a grill must be reserved. Hope that answers your question.

All free

Picnic tables are free and first come, first serve. They have grills. Beach access is free as well.