Playa Conchal area or Manual Antonio NP? Or any other advice 😉

Our priority is stuff we can't see in the states, but would also like to hit a beach if time allows. I'm assuming we can't fish and or snorkle in the NP? Is that true? We'll be renting a a car and plan to go to Arenal, Monteverde and wherever is recommended. Honestly, I always plan our trips, but Costa Rica has me stumped. Maybe because there's midi so much to see. Feel free to drop an itinerary that you enjoyed.