When I write the heroes' diaries I try to keep the tone similar to the tone of the original, bearing in mind that it's seen through the hero's eyes, so in Henry Tilney's Diary I want to reflect the fact that Northanger Abbey is a Gothic, albeit a kind of spoof.
I agonised over this idea for ages because I couldn't see how to do it. In Northanger Abbey it's Catherine who brings the Gothic element because she imagines herself to be in one of Mrs Radcliffe's novels, but with Henry being a very different kind of person it was difficult to see how to do it. And then a line in the original gave me the clue because Henry and Eleanor read Gothic novels together.
This is perfect from my point of view because I can have some Gothic scenes, with thunder rolling outside the Abbey window and Henry and Eleanor sitting indoors, reading one of Mrs Radcliffe's novels by candlelight. If I add in some over-the-top Gothic elements like a few flashes of lightning the Gothic scene will be set.
It will also allow me to do something else I wanted to do, that is, introduce some text from The Mysteries of Udolpho. I know that not everyone will have read Mrs Radcliffe's classic, and that some people won't realise it's an actual novel, so this will allow me to give them a taste of the book.
I want to include something about the black veil, because Catherine and Isabella mention this in Northanger Abbey. Readers in Jane Austen's time would have read the scene and so they would know exactly what Austen was talking about. I want to give modern readers the same kind of knowledge.
The only thing I can't decide at the moment is whether or not I should have a later scene in which Henry and his sister read the passage that reveals what lies behind the veil. Would that spoil it for anyone who hasn't read Udolpho, or do I anticipate that everyone who is likely to do so has already read it and therefore they know the answer to this question?
At the moment I can't decide. One thing's for sure, there will be some very Gothic scenes in Henry's diary.