What works and what doesn't in The Pomise of Happiness

It should come as no surprise - given the title of the novel (The Promise of Happiness - why not btw The Pursuit of Happiness, as much of the novel takes place in the U.S.?) and the epigraph from Updike - that this ambitious novel (Justin Cartwright, 2004) ends w/ a wedding celebration, the classic ending for a "comic" (in the broadest sense, not a funny novel by any stretch not is it meant to be) novel. I was only surprised that, given the many amusing passages in the novel where the characters and the author comment on the occasional cliche'd situation - raining outside when the character is sad, e.g. - that Cartwright didn't include some reflection on the conventionality of a novel ending in a wedding. That said, my overall take on this novel, little-known in the U.S., is that Cartwright is really intelligent and he delineates a complex set of family relationships and goes to some depth into the psyche and fears and anguish of some of the lead characters, the father, Charles Judd, in particular, a deeply troubled man who is unwittingly cruel to those closest to him - but that Cartwright never really gets a plot off the ground. Much of the plot centers on the older daughter's (Juliet/Ju-ju) getting spring from prison in NY state, where she'd been held for two years for her role in the sale of a stolen Tiffany stained-glass panel. I don't want to beat a dead horse, as I've mentioned this in a few previous posts, but this plot element never gets off the ground, and in particular the twist near the end, which I won't divulge, is preposterous; the novelist seems to have little knowledge as to how the American judicial system works - it's almost as if Juliet doesn't have a lawyer working for her - and some serious misperceptions about how the media works as well: there would not be hordes or reporters and TV crews to film the release from prison of this complete noncelebrity jailed (itself unlikely) for a single act of aiding an art theft (maybe if she's helped steal a masterpiece, as in the Gardner museum theft); also, the NY Times does not pay for stories, sorry, this is not the Daily Mirror. Perhaps these are just quibbles, as there are some pleasures in reading this novel and I'd probably read another Cartwright novel if recommended, but this one has highs and lows, in other words, it's uneven.