Getting to appreciate more of Trollope - if you can accept situations improbable even by Victorian-fiction standards

I am enjoying Trollope's Dr Thorne as I get deeper into it - hoping I can make it thru the 1,700 (electronic) pages! - and have found that I had to go back and re-read large sections of the early chapters to figure out some of the characters and plot developments - he gives so much background at the outset and you just can't tell what info is significant and what is incidental - that's part of what I didn't like about AT at first, but as you get deeper into the novel things start to cohere and the characters start to differentiate, at least the major characters do (the fact that Frank Gresham has 4 sisters does not help matters, I'm still trying to figure out which one's engaged, which one's Mary Thorne's friend, etc.). As w/ so many English novels of the era, the plot is build on the conflict between title and wealth: the old named families believe they are better than others by virtue of their birth and heredity, and they would not dream of diluting their "blood" by marrying a "commoner" - but this is changing, as some of the old families, like the Greshams in this novel, have squandered their wealthy so it's OK to marry someone as long as he (or she) is very wealthy - yet not without scorn, there's much derision about someone's marrying the son of a tailor and about an available singe woman whose family made money through some kind of ointment. These matters converge in the person of Mary Thorne, who is a staunch believer in fixed social class and inherited stature, so much so that she spurns the attention of Frank Gresham because she thinks her stature is too far beneath his - so in effect she isolates herself from anyone to whom she's likely to be attracted. The plot "thickens" around 1/4 of the way through the novel as we meet (or re-meet) Sir Roger, a former stone mason (who killed Dr Thorne's brother in an act of vengeance and served time in prison), now a very wealthy builder or contractor but still a roughneck and alcoholic. In a relationship that truly strains probability even by the low standards of Victorian fiction, Thorne and Sir Roger are now close friends and Sir Roger does not know the secret about Thorne's niece Mary: that she is actually Sir Roger's niece as well (born out of wedlock, mother fled the country leaving daughter behind) - if you can accept that premise there's a very intriguing twist as Sir Roger names in his will his oldest niece or nephew, who he assumes to be someone he's never met living in America - not knowing that Mary is his niece let alone his oldest.