There are Rovers you can hire when you show up at Tintagel. Question: How far up do they take you? And if there is still a steep climb after they take you as far as they can go, is the footing fairly secure?
We were there June, 2015. The Rover took you down the hill from street level to the shop where you could buy a ticket and of course also goes back up the hill.. Two pounds to use it, but the money benefits some local charity. At the bottom of the hill by the shop you could see down into the cove and get a distant view of the castle. To get up to the castle, you MUST walk. It's several hundred uneven steps up a cliff side. The steps are slippery when it gets wet. The castle ruins are very interesting once you complete the climb.
The only other thing to see in Tintagel is The Old Post Office which is actually a late medieval home. If you can't do the steps up to the castle, it's not worth going to Tintagel , which seems to live on tourist dollars, including excessive charges for parking. Visit Boscastle and Port Isaac instead.