Secret Woods
The Secret Woods is a 60 × 32 clearing behind the fallen log, and dense enough that only nine of its tiles are diggable. Nothing is patched in: the shipped map already carries the crow shop in its closed state, and the statue's eyes are a render-only swap, so what you plan on is the file as it ships.
What you can place here
You can place objects, machines, furniture, fences and paths here; crops and buildings stay on the farm.
Other valley maps
Ginger Island NorthGinger Island SouthGinger Island South-EastGinger Island EastRailroadBackwoodsSummitPelican TownCindersap ForestMountainPelican BeachCalico Desert
Start a plan on any of them from the Valley tab of the New-plan picker in the planner.