The irony of this particular lament is the the guiding metaphor for reading text on computer screens is, in fact, the scroll. So it's really simply just a matter of making one's self write without editing.
Nate: 
Literature | How would Jack Kerouac cope with Microsoft Word? Not very well, a blogger imagines, for “the birth of the computer has led, largely, to the death of the genuine stream of consciousness novel.” It “allows us to delete, shift sections around and continually edit, in the way that Kerouac, writing on his lengthy scrolls [for “On the Road”], could not.” [Guardian]