Bonfire Islands and Kiwimbi Beach are my favorites. It's a shame most people just stick around in the Grounds. There's never anyone in Kibou Ridge, either, and even Eastern Pass and Cherika Valley tend to be very quiet most of the time aside from the occasional wolf RP.
It's so strange since most of the old FH maps always had people in them, save for like... Temple of Dreams, Atlantis, and Last Cave which were usually empty in my experiences.