Here’s my take: leave your bag(s) in San José (hotel left luggage?) and use a soft bag or small duffel for your clothing, etc. You won’t need so much at the coast, and local laundering or washing in your bathroom will help. (And do take insect repellent if you don’t want to be dinner at dusk for the “purujas”, no-see-ums that can be pesky and provide weeks of itching if you have no antibodies because yiu haven’t been there before.)