Great but unreable v great but unknowable novels

This will be the last time: I tried once again to get absorbed in William Faulkner's Absalom, Absalom!, having set it aside some months ago when I got mired in the extremely long chapter in which Quentin's northern preppy roommate, Shreve, narrates to Quentin a great swath of the history of the Compton family post Civil War, and after each of Shreve's ludicrously detailed, operatic passages - completely impossible as examples of anyone's speech, ever - Quentin simply says, "Yes," and Shreve goes onward - Faulkner's really having fun her making fun of his own loquacity as a narrator and, I believe, his taciturnity as a social being. In any case, I literally could not get through this chapter, or for that matter this novel - it would be simply impenetrable if not for the lifeline Faulkner (or some merciful editor) tosses us with the cast of characters and the timeline at the end (similar to the preface F. added to later editions of Sound and Fury, which to first readers must have been entirely daunting - much less so today). A, A! is, however, impenetrable: many list it among the great books, but I have to put it among the great but unreadable books, alongside Finnegans Wake, Man Without Qualities, possible Gravity's Rainbow. These great but unreadable - honestly, who's finished any of them? who's understood them? - novels stand alongside others that a great but unknowable, books so vast in their scope and in their authorial intelligence that we can read them - I have - but that it seems no number of readings could possibly encompass everything the author has in his (or her, if you like) mind: Ulysses, Moby-Dick, In Search of Lost Time, to name three, each of which I've read multiple times (at least 1st two volumes of Proust) and feel each time I can never "get" it all and am not meant to, or perhaps not able to - but just to approach the mind of the author, to gain some access to the conciousness of Joyce, Melville, or Proust, is enough, more than enough.