We went February 2020, right before covid blew up. We did not stay at your resort, but rented a VRBO in the same Guanacaste province, but a bit south. It was beautiful. We stayed in Playa Flamingo and there are loads of places on VRBO.
We flew to San Jose and rented a car, and it was about a four hour drive to get there. Being our first time, and having kids along, the arrival times were much earlier and we didn't want to worry about driving in the dark. But now that we've done it, if we ever did it again, it would be significantly closer to fly to Liberia, though it did cost more.
Our area was relatively quiet. We did go for an evening to Tamarindo, which if you want more lively area to stay, that would be it.
I would get a car again, it was helpful to have to get around, but it could be done without it if you pay for a transport service to take you places. I assume if you've been there, you're aware that it takes forever to get anywhere.
Also if you've been there, I am sure you're aware of costs of things - I was surprised at how much things cost, I figured it would be significantly cheaper . Grocery stores and things close quite early as well.
We went to Cipanci National Wildlife Refuge and took a boat ride down the river. Lots of gators, birds, monkeys, lizards - beautiful. Though our boat died about 50 times and sometimes I wondered if we'd get back on the boat, but we did manage not to have to swim with gators.
We drove through Rincón de la Vieja National Park and there is a waterfall there that is relatively easy to walk to. You can swim at it. It is cold.
There are tons of ATV rentals, which we got one big enough for four, and rode it to a ziplining place (can't remember which, but there are numerous).
There's also a ton of horseback riding places, which we randomly chose one and rode through the trails down to the ocean. Sorry, I can't remember the name.
This was our favorite thing to eat - https://www.facebook.com/vidabowlscr - Vida Bowls.
Did an afternoon/supper/sunset sail with this one - https://www.panachesailing.com/
There was loads of time to explore wherever we stopped, swim, snorkel, paddle board, kayak.
Some of the group did a fishing trip, also loads of captains to take you out. I can't speak for it, fishing is not my thing. But they seemed to enjoy it.