Hi Gordon,
Manuel Antonio is beautiful! You’ll have a lot of fun. Some must do activities:
1. Sunset at Barba Roja restaurant (dinner and drinks) and/or La Mariposa Hotel (drinks at the pool bar). Best craft beer selection at Barba Roja and a great specials menu.
2. A visit to the national park. Go first thing in the morning as they cap visitors. Also, hire one of the licensed guides at the front gate or ask your hotel for a recommended guide. Well worth the $20 per person because they have such knowledge of the flora and fauna. Also, bring your swim suit and towel as the beaches in the national park are the most beautiful in the area.
3. Visit Playa Biesanz. it’s a “secret” beach well off the main road that is deserted many days of the week. Good snorkeling too.
4. If you’re into grilled meat and seafood, go to dinner at El Lagarto – my fave restaurant in the area.
5. Rainmaker Park is an private wildlife refuge about 30 minutes north of MA that is pretty cool and you could either drive there if you rent a car or take a shuttle. Less crowded than the national park and very wild.