How fast can you build all of the Striiv Myland?

As you can see from these two pictures, I managed to plant on every lot on every island:

So how long does that take?  Well, if you average close to 10 miles and 2800 stairs per day, and if you buy plants that yield 4000 gold per day or more, you can do it in...

15 days.  Maybe you can do it faster, but with the 1 million energy-per-day limit it will be difficult.

So much for my 15-day experiment.  I think I will take a break for awhile and do more swimming and weightlifting, activities I have neglected for months since they don't earn Striiv energy :)