The advice I always give to my undergrads when they attack a novel from a historical period they don't know well is to start by listening out for the voice.
So, read page one- when you get bogged down, later on on the page, go back to the start of page one. Do this until you have read up to page 3 by which time you will have tuned in.
Persuasion is a bit extra tricky as the first para is a bit of a contemporary in- joke ...
Maybe at the end of the previous meeting you could do para one together as a collective toe-dipping exercise.
Tell them it starts with an in-joke about a nobleman obsessed with himself. Then ask them to think about what Austen's view of Walter Elliot is.
This exercise might help them to get a grip on her tone and method in readiness for the fantastic story to follow.
(Sir Walter Elliot, of Kellynch Hall, in Sommersetshire, was a man who, for his own amusement, never took up any book but the Baronetage; there he found occupation for an idle hour, and consolation in a distressed one; there his faculties were roused into admiration and respect, by contemplating the limited remnant of the earliest patents; there any unwelcome sensations, arising from domestic affairs, changed naturally into pity and contempt, as he turned over the almost endless creations of the last century - and there, if every other leaf were powerless, he could read his own history with an interest that never failed - this was the page at which the favourite volume always opened: ELLIOT OF KELLYNCH HALL)