Eh, too long? Now that I'm focused on the endgame of my two remaining on-going comics, writing has taken a back seat and is mostly just whim-driven.
But last year when I was sick and didn't have the energy to draw, I just typed. So I could get a chapter done in perhaps a week? But I enjoy jumping around the manuscript, working on whichever part I feel strongest about in the moment.
I suppose I can focus on writing sequentially and make a goal of completing so many words within a day, but I can't guarantee the end product would be as good. At least it's less of a time-sink to edit and rewrite parts of a novel than to redraw comic pages.