Large free car park opposite the farm shop
Mainly flat with slight hills but not too strenuous. The woodland area however is quite steep with steps and windy muddy paths, but can be avoided easily and still have a nice walk. No stiles.
Right opposite the castle entrance there's a bridge over the river and a great shallow sandy bank leads to this perfect for a splash. Couple of other points to access further along the river too.
Lots of bins around the car park, and also one at the far end of the woodlands where the path leads off towards St Anne's Hill
The farm shop and cafe comes highly recommended, and apparently they allow dogs too.
Heading down the track from the car park there's lovely views across the fields and polo pitches (?), and it's a nice wide path that's fenced off so great off lead running time. If you walk up to the castle entrance and take a right over the bridge directly opposite, you can follow the river to the left which leads you into several paths through the woodlands and along the river. I took the steep path up the steps, and explored the small woodland for a bit before I looped back towards the castle, and extended the walk a bit more by walking round the castle itself, and the adjacent rugby and cricket fields to come back to the main path leading back up towards the castle.
From the woodland area there are plenty more path choices, and you can also walk into the old town of Midhurst from here too.
It can be busy with walkers, joggers etc. but it's a beautiful walk with great sights and the castle ruins are quite spectacular.