JA makes a reference to "Camilla" in this letter:

Tomorrow I shall be just like Camilla in Mr Dubster's summer house; for my Lionel will have taken away the ladder by which I came here, or at least by whihc I intended to get away, and here I must stay till his return..

This refers to an incident in the novel where Camilla and Euginia are stranded in Mr Dubster's summerhouse; sadly incomplete for it has no permant acess by stairs) they had ascended into it by means of a ladder which is taken away by Lionel.

Here is the relevant passage from the novel:

He then requested them to make haste to his summer-house, because his workmen would be soon returned, and he could not then spare a moment longer, without spoiling his own dinner.

'My summer-house,' said he, 'is not above half complete yet; but it will be very pretty when it's done. Only I've got no stairs yet to it; but there's a very good ladder, if the ladies a'n't afraid.'

The ladies both desired to be excused mounting; but Lionel protested he would not have his friend affronted; and as neither of them were in the habit of resisting him, nor of investigating with seriousness any thing that he proposed, they were soon teized into acquiescence, and he assisted them to ascend.

Mr. Dubster followed.

The summer - house was, as yet, no more than a shell; without windows, scarcely roofed, and composed of lath and plaister, not half dry. It looked on to the high road, and Mr. Dubster assured them, that, on market days, the people passed so thick, there was no seeing them for the dust.

Here they had soon cause to repent their facility,--that dangerous, yet venial, because natural fault of youth;--for hardly had they entered this place, ere a distant gimpse of a fleet stag, and a party of sportsmen, incited Lionel to scamper down; and calling out: 'I shall be back presently,' he made off towards the house, dragging the ladder after him.

The sisters eagerly and almost angrily remonstrated; but to no purpose; and while they were still entreating him to return and supposing him, though out of sight, within hearing, they suddenly perceived him passing the window by the high road, on horse-back, switch in hand, and looking in the utmost glee. 'I have borrowed Jacob's mare,' he cried, 'for just half an hour's sport, and sent Jacob and Coachy to get a little refreshment at the next public house; but don't be impatient; I shan't be long.'

Off then, he galloped, laughing; in defiance of the serious entreaties of his sisters, and without staying to hear even one sentence of the formal exhortations of Mr. Dubster.

Book IV,Chapter II

Poor JA: I really sympathise with her frustration with regard to the limitations on her freedom of movement.No wonder she made Captain Wentworth give Anne the luxury and freedom of a "very pretty little laudalette".

Jane Austen was one of the original subscribers to Camilla.Le Faye in Ja:A Family Record notes:

Fanny Burney, or Madame d'Arblay as she then was,had advertised her new novel Camilla for subscription in 1795 and it is possible that the Austen's cousins, the Cookes of Great Bookham, who were neighbours of the d'Arblays when the later were living there from 1793 to 1797, had canvassed their connections to obtain subscribers.Jane's name appears on the list,the subscription being one guinea for the five volumes of the work, and following its publication on 1 July 1796 she had been enjoying it very much as is shown by her references to it in these letters....

p 98,