https://www.interbusonline.com/home/home.asp They have 2 shuttles a day for around $35. They will take you direct from one hotel to the other.

Thanks!!

At an avg price of about $300 a night for both places who cares about "cheapest. Jump on a nature air flight in Fortuna and fly down there instead of spending a whole day bouncing around in a van.The flight is an absolute rush !

Flights are almost always a bad idea no direct flights quite expensive weather delays you see very little.very cheapest thebusschedule.com not great Interbus or best for me
servicecarrental.com out of SJO for the whole week self guide save a tonne on costs I always have the freedom of a car.
odysseytours.com if well budgeted and a car rental fraidy cat.

Good luck!

odysseytourscr.com sorry for link pooch.