I've spent more hours than I'd like to admit trying to get clean PDFs of stories I love. The real struggle often isn't finding any PDF, but finding a good one—properly formatted, complete, without wonky OCR errors or missing chapters. If it's a traditionally published novel, checking the publisher's own website sometimes yields a surprise; I once found a free, high-quality PDF sampler for a series directly on Tor.com, which was a perfect offline preview.
For web novels or serials, the landscape is trickier. A lot of readers create their own compiled PDFs from updates, but quality varies wildly. I lean towards communities dedicated to specific authors or genres on forums. You'll often find a stickied post with a maintained, fan-made PDF that's been proofread by several people. It feels less like piracy and more like a shared passion project when it comes from a dedicated fan hub rather than a random aggregate site. The trade-off is you might have to engage a little, maybe thank the compiler, which is fair.