Maps all show this area simply as woodland, and if you look at Google Earth all you can see are the tops of trees. 

It's always been a favourite place for us.

It's possible to let dogs and children wander free, and there are several paths in different loops.  An 'I Spy Book of Stackpole Woods' would include ticks for a stone seat, an ice house, a stone pavillion, a walled garden, a pergoda (not the original, unfortunately), greater horseshoe bats (near dusk) and some recently-planted trees more suitable for car parks.

Take the path next to the ticket machine, and turn right.

Incidentally, if you find yourself in this car park in the summer at dusk, try standing next to this gate:

At first, nothing will seem to happen, but then, quite suddenly, you'll get your tick for the bats!