I don’t see TSA being on board with blind folding children (human trafficking signs) ... also they have to hold they’re own boarding pass and be able to answer question (Including where they’re going) so the morning of might have to be surprise enough.

Manuel Antonio is fantastic. Took the kids 2 years ago. So much to do, beach, wildlife, waterfall tours, zip lining, etc. also highly recommend Arenal / La Fortuna. Check out Hotel Los Lagos, has several thermally heated pools with slides and onsite activities.

Puerto Viejo is my favorite place on earth! Beachy, surfers, bikes, food, and amazing people, on the Caribbean coast 💛💛

I just stayed there and the resort and people on the beach right at the resort offer some really good cheap excursions

I traveled solo for 6 months in CR when I was 16 and it was amazing! I HIGHLY suggest you check out Uvita. It is one of the most amazing places on earth. The public transport is so easy to figure out and it goes everywhere!

I just recently learned that you often have to switch rental cars at borders, so that might be something you want to look into

I went for a week in October of 2018. Saw rain most days, but it was off and on through the day, moreso in the early morning. But it's 80+ degrees and rain. It didn't really bother me.

In my experience they all have some hidden fees once you arrive. Even though the online booking hides it. What airport are you flying to?