I led a 4 week expedition to Costa Rica in July 1997, less than a year after starting on insulin. I didn't take a Fio wallet, just a stainless steel vaccuum flask that I already owned. Plus, a plastic tub given me by a pharmacist friend - I removed the label and wrote "insulina, s?lo en el refrigerador, no en el congelador, no en el calor" "insulin, only in fridge, not in freezer, not in heat" in permanent pen on both lid and pot - for use when we stayed at hotels / guest houses / shops (during home stay with family with no fridge), in between camping.
Hope you like rain, mud, rice and beans. June is in season called "invierno" in Costa Rica, but really it's rainier season (it rains to some extent all year round, just more May to November). So, unsurfaced roads acan become impassable to vehicles, although you can usuallly get through on foot, river crossings permitting. Of course, if you visit Canalete, you'll find a very fine footbridge, built by my friends in 1992/3. It's a tiny village, with no reason for tourists to visit.
It was great visiting new places and places I'd last visited when a leader an international youth & development project in 1992/3. At Santa Elena, the community run rainforest reserve near the much better known (and largely foreign owned) Monteverde, I met a young man who I didn't know, but as soon as I mentioned the name of the organisation (with Costa Rican / Canadian / Australian / Guyanese members), in Spanish, obviously, he insisted on showing me round vistor centre, giving me a guidebook for trails, refusing entry fee or payment for book etc.
Viajar bien!