And don't forget that there are plenty of other visitors to the beaches, in addition to the tourists, who are certainly into people-watching!! ...and not always terribly impressed or entertained by what they see!!
Manuel Antonio is just 3 hours from San Jose and only 35 USD by shuttle bus Interbus or GrayLine. Be sure to stay in Manuel Antonio village rather than the base town Quepos, as then you are only 5 minutes from both the beach and the entrance to the National Park.