You really don't need it as much as you might think you do. I've written a whole article with virtually none, and it worked out fine. I don't think a reader will even miss it. I don't think a reader will even say, "Wow, a whole article with no signposting," because the absence of it won't even register. Signposting is distracting, but its absence is not. I guess there could a few academic readers who say, "What's this about, no jargon, no self-referential signposting, no acadamese. This person obviously doesn't know how to write." That's a risk I'm willing to take.
What about an introduction to a book? Don't you have to say, "In chapter 4, I will argue that the novels of Roberto Bolaño..." ? As a first step I would suggest something like this. "The novels of Roberto Bolaño--the subject of Chapter 4--..." The rest of the sentence will state your argument without saying that it is your argument. Of course you wouldn't use that exact formula in each paragraph of the chapter summary. As long as the reader knows that it is a chapter summary, you might even get away with suppressing even those parenthetical reminders. What if you were summarizing the last chapter, then you could start out that paragraph with "The novels of Teresa de la Parra, finally, ...." It would be implied that this is the subject of the last chapter. I'm not against discursive markers like finally, that simply signal the stages of a discussion.