I picked most of these because they only work if you read them slowly--often out loud--and let the language become music. they are not really about plot, they are about flowing images, sounds, thoughts and perceptions:
Isolation reading list: Ulysses by Joyce; Gravity's Rainbow - Pynchon; Tropic of Cancer - Miller; Baudelaire; Proust (all 6 books); Decline and Fall of the Roman Empire - Gibbon (all 16 volumes); and for light reading the Hyperion "quartet" by Dan Simmons. One could add One Hundred Years of Solitude, The Plague by Camus, Call It Sleep by Roth, and No Exit (and other plays) by Sartre.
At present I am rereading Miller and Gibbon and Proust--I just finished Pynchon and have read Ulysses for the 17th time last year... I'm also reading "A Distant Mirror" about the 14th Century Plague and its impact on religion, economics and politics; "Turning Points in the History of the Mid-East because: OIL. My guilty pleasure books are too numerous to mention, but probably the best lately has been the middle books of King's Dark Tower Series