This is a wonderful ruin.
The castle is about 2 kilometres north of the small town of Lostwithiel on the river Fowey, down Cornwall way.
Wheelie access is pretty good, after a steep ramped path to the office/shop.
There are two wheelie parks nearby, and apparently an accessible loo.
There is access inside to the castle and the ground floor rooms, and around the moat.
The shop helper must unlock the side gate as the main path has a few steps.
The paths around the ruin are grassy however, and fairly steep. I had no problems, but it might be a different story if it had rained recently.
The views are beautiful.
The shop has some humble local meads and such.
Curiously, the castle, as part of the “Duchy of Cornwall“, is owned by Prince Charlie (as of 2016).