Not a plug for this thread, but worth a mention. A few years back we visited Camber Castle, which on the face of it is pretty uninspiring, except it is a pleasant walk from Rye and the couple who do the tour (if you can call it that) are knowledgeable, passionate and engaging. To call it a tour is more than a slight exaggeration, but we had a lovely chat and I learnt a lot. £3 for adults, free for Under 16s.