Dear Jerusha: I can't seem to read my novel from start to finish – perhaps in one sitting, perhaps over a few days – without changing things. I’m not a fan of directionless editing, but I’ve never read my book without spying at least a hundred words that need cutting – or maybe a couple of grammar catastrophes. I can’t just sit, read, relish. In fact, I think this type of editing – when all you want is to read and assess the flow – massacres the enjoyment: it’s disruptive and dispiriting, constantly illuminates the flaws, poses questions such as, ‘What else needs tightening?’ or ‘Where else have I used double dashes when commas would be better?’ Obviously, no aspiring writer should ever ignore these questions – but has anyone found a way to just let go and enjoy the ride?
I'd just swatted away a six-foot iguana, and was re-reading your question so as to start answering it, when your phrases "relish" and "enjoy the ride" made me pause for a moment. Without wanting to be a Calvinist about it, I'd suggest that relish isn't necessarily the most useful reason for a writer to re-read their work. We all love the sound of our own writing voice - except when we're hating it - and reading immersively, for pleasure, is essentially uncritical: witness how we turn our writerly geiger-counter right down when we're reading an entertaining but badly-written book. If you winced at every second-hand phrase and stereotyped character, you'd never discover who dunnit. But I'm assuming that the core of your question is about reading which is highly purposeful - part of your writing process - but which doesn't get bogged down in editing.
The whole point of reading through your novel is to try to read it as a reader does. Okay, a critical, concentrating reader, but you're still trying to experience it in that way: as experience-in-time, which is essentially what narrative is. But as soon as you stop to disentangle a paragraph, or flip back to check something, you're no longer doing what a reader does, and so you're losing touch with that experience-in-time. It's not just because if you start fiddling at bits and pieces - as I suggested here - you're liable to make as many muddles as you solve. It's not just because reading it with no particular purpose is using up the limited number of reads you have before it goes stale to you. It's also because you lose touch with the time aspect of the experience.
So I'd suggest that whatever you do, you don't let yourself stop to actually edit. Of course you can correct a typo or stick in a comma where you found yourself breathing in a sentence. But if what needs doing can't be done within the normal flow of reading, just mark it and keep going. I would urge you to try it on hard copy, because it's much harder to get embroiled in editing, or at least to learn the keyboard short-cuts for adding a note in your WP program. Emma has a whole repertoire of quick scribbles like "awk" for an awkward phrase, and "?res" for checking if the research is right."?PL" for language which is doubtful for the period, "wrong for voice"; "sort out para"; "skimpy" etc. etc. It can include general issues: "?Would she say this yet"; "?not good enough reason". And "?dashes not commas check throughout", is what she would write for your problem above.
In other words, use the read-through for finding problems, not solving them.
Emma can only do it on hard copy, and she's not the only one - on screen it's too fiddly to mark something, and too easy to get embroiled. Reading aloud helps tremendously, partly because the brain processes words for reading aloud in a different place from words for reading to yourself, and so it's more like reading something unknown. But it also helps because there's a stronger imperative to keep going: you're more aware if you've stopped reading and got embroiled.If the pause to change something would be long enough for a restless 6yr old to get bored, then it's too long for your attention to hold to the story and overall shape. Scribble and keep going.
Reading hard-copy manuscripts is one of the writerly jobs that you can do away from the computer, but they're awkward beasts in a train or a wind or on a lap, and someone has just told Emma that they upload the MS to their Kindle. You can mark and make notes, but you can't really get embroiled in changing things - to do that you put the MS back on the computer and get stuck in. Emma says that's the first reason she's heard which would make her contemplate buying an e-reader.
Once you've found all the problems that a reader would find, you can then work your way through solving them as a writer would solve them. Then you may flip back to find something, hop through the book dealing with one issue the whole way through, move chunks of stuff about. Though I'd still suggest basically working forwards through the novel with any given job. That way you hold onto your sense of the order and structure of things, if not the pacing.
Of course, once you've solved every problem you found, and the further problems that your revising threw up, you'll have lost some of your sense of the novel as an experience in time. And the new stuff tends to stick out at you, like the new rug in a room which has otherwise been the same for a decade. It's hard to judge how it appears to a reader for whom everything is equally (un)familiar. That's the point at which you need to stand back from it again, and re-capture that sense of how it reads. Time for some drawer-time, perhaps. And then another read-through?