We had our honeymoon in Costa Rica through Trailfinders, travelling around and it was a brilliant experience. Although in hindsight it would've been so much cheaper planning and booking it ourselves! Our route was San Jose - Torteguero - Arenal Volcano - Monteverde - Manuel Antonio. All travel was by bus/minibus with the occasional water boat which was nice! Whole trip was just over 2 weeks but I remember at the time they had a shorter tour.
We went in November 2017, and from what I remember I wasn't too hopeful about the weather but we were very lucky and on the times we did get caught in the rain we were very thankful as it was so cooling!
San Jose wasn't my kind of place, but we don't like cities and didn't feel entirely safe in the evening, glad we only booked the one night to get some sleep before our journey.
Torteguero was lovely, we stayed in a rainforest lodge on the river. We woke up in the morning to howler monkeys (which was something else! ). There were plenty of excursions within the compound, although we decided to take a trip to the town of Torteguero. It was quite upsetting to see how the locals lived, but everyone was very helpful and pleasant. It did however make us realise how lucky we are to live as we do. Very hot and humid, what we expected from a rainforest.
Arenal was an incredible experience, lots of activities such as hanging bridges through the forests, zip lines and we had an amazing horse trek down to a waterfall called La Fortuna. The hotel pools had hot springs as most of them did, which was amazing. Still quite humid but nowhere near as bad as Torteguero.
Around this point I developed an awful flu as we travelled to Monteverde, so I wish I could say more about this place but I can't :( it was a beautiful place, very green but quite a bit colder as you're so high up. There was an animal sanctuary that was really enjoyable!
Manuel Antonio was incredible. Beautiful beaches, squirrel monkeys everywhere and just a beautiful place to finish off and relax for a few days after lots of adventures! There was a national park that we visited on our last full day that had the most incredible beach. Wish we found it when we first arrived as we would've spent every day there. You had to pay something equivalent to 10 dollars but it was so worth it.
Also, we read online that although their currency is the colone, American dollars are widely used. While this was the case it felt like such an effort to use dollars and we wished we just taken all colones instead. If you pay in dollars, your change is in colones, so we'd fins that we had enough money at times, just not in the right currency of that makes sense.
It's such a beautiful country, I think you'll love it no matter where you go! Hope that helps. Give you some ideas!