A good, short fiction novel is Oscar Wilde's The Picture of Dorian Grey. Sherlock Holmes is also good: his novels (also relatively short) include: The Sign of Four, The Hound of the Baskervilles, The Valley of fear, and A Study in Scarlet. My favourite was the Hound of The Baskervilles. I don't think listening to audio books constitutes cheating because you're still taking in the novel: my sister has Dyslexia and that's how she's doing her summer reading right now.
As for nonfiction, I enjoyed Temple Grandin's Emergence, a memoir about her childhood. It would be a good way to introduce your teacher and/or peers to ASDs if you have any projects due for the books you're reading.
Regarding completing the work: InTheDeepEnd's suggestion is a good one: it's how I got my reading for my college literature class done. Another suggestion (not that I would condone this) is to read as much as you can, then in the last two or three days, use SparkNotes or CliffNotes to get the gist of the remaining chapters until you have time to finish them.
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"Survival is insufficient" - Seven of Nine
Diagnosed with ASD level 1 on the 10th of April, 2014
Rediagnosed with ASD level 2 on the 4th of May, 2019
Thanks to Olympiadis for my fantastic avatar!