A hidden gem in Monterey for families with kids is the Dennis the Menace Park at
777 Pearl Street.
As parents of an energetic 4yo we are always on the lookout for a kiddie attraction on our day trips. We like to do this first, to provide some relief after the long drive (for all of us) as well as to use up some energy so we can all have a more peaceful time for the aquarium, sightseeing, lunch etc. So we drove up here first thing, reaching at about 10 am - there is plenty of free parking and clean restrooms.
There is no entrance fee, and once in the park is just delightful, and lots of play structures with many happy little kids and big kids playing. There is a roller slide - kinda like a assembly line conveyor belt - looked painful but was very popular, everyone wanted to try it! My son enjoyed the rope bridge and the wooden maze the most and was so happy there it put us all in great spirits for the rest of the day. There is also a rock climbing wall, skate park and paddle boat pond behind this park.