Google maps link was a little wonky for me, but... I *think* you have the beach club in the right location, but could also be on the south side of that big resort. Amanusa itself is up the short trunk road you have marked--meaning proceeding west from the Golf Club, take the right after 1 km or so, don't keep going straight up the road all the way. I am sure of that because many of Amanusa's rooms sit adjacent to a golf fairway. Not sure where the residences are relative to the rest of the resort--that could be them at the end of the road, but we didn't go there; maybe somebody else can confirm?