Agreed: Floater Island is the most reliable. It's a good location to try and rush to because the plants you get there also allow you to build a self sustaining base so you don't have to worry about food as much anymore.
I dislike "jumping" the storyline for an early trip to the floating island.
If you're like me, AND want the more "juicy" location... you usually get Lifepod 3 (damaged seaglide), then Lifepod 17 (Ozzy). When you are getting close to pod 17 (Grassy Plateau, the one with the red grass), your PDA tells you about a "nearby cave system" -- that's the Jellyshroom Caves, the one with the big pink mushrooms (and the Crabsnakes...).
If you explore that a bit (and who wouldn't, there's Shale Outcrops, Lithium, and Magnetite to be had), you will find a platform with a couple of cargo boxes and an Abandoned PDA. That one will give you the location of the Proposed Degasi Seabase (250m), in a different section of the Grassy Plateaus.
That seabase has Multipurpose Rooms, Observatory, Water Filtration Machine, Double Bed, Wall Planter, Spotlight, a databox, several PDAs (5 IIRC), and scattered around it several scanable items, usually including the Thermal Power Plant.
You will be pointed toward the floating island shortly afterwards, via the Lifepod 19 event (Second Officer Keene). Around pod 19 you will find Rubys and Gel Sacks, allowing you to construct Aerogel and thus the Thermal Power Plant and the Water Filtration Machine. At the lifepod you find a PDA with the rendesvous coordinates, which will lead you to the nearby island.
Of course, at this point the island gives you "only" the alien tablet, the growbeds, plant samples, and the Bulkhead blueprint. But you haven't "jumped the storyline" as much as you do when you go to the island first.