homeschooling abroad in costa rica

Hi, we moved to the remote Carribean Coast of Costa Rica 18 months ago, my son is 13 and he has completed 5th and 6th grade here in a Waldorf school nearby, we do not have any satisfactory options for 7th grade and we are considering homeschooling.  We do not live in the Us anymore and do not inted to move back, however we want to offer him an education that he can use there if he chooses to go to college in US.  We are at a loss how to start, what are testing requirements, what kind of records do we keep.  We want to continue the Waldorf or something similar education he has been receiving.  It is very flexible and addresses the whole child at the same time we want to make sure he is prepared.  He speaks english and spanish. Does anyone have any suggestions? How do we get started, what is the best way, are there resources in Costa Rica.  This all seems exciting.