If you are staying in Atlantic Road you cannot get much closer to the castle and is a 10 min walk.
The other places of interest are all well within walking distance and there is also a bus service which runs more or less hourly if you want to go further afield or just to get back to Tintagel.
This is perfect walking country but you must be prepared for hills!
There is little in the way of flat walks here but the scenery is stunning and unspoilt!