in a bolder
the top
It is near the beach in east corner of the isle.
About halfway between the dock and the eastern end of the isle, by the northern beach
there is no riddle box
There none.
In the northwest corner of the isle :)
If you follow the western edge of the part of the isle that bumps up south, it will be in the forest, or if you head directly west from the dock and go a couple stride lengths south you should run in to it also.
It's near the north-eastern side of the forest
There isn't a riddle box on every single Isle, but most have one... so there may not be one on Brown,but there might be...
Switch Horses
On the light green bit between the three forests just south of the top river. You can find a screenshot of the location in related links.
It is by the southern south west edge of the light green grassy area in the center. -CalicoFilly