The blue square is just the sky in your model. You could turn it off and update the style so it isn’t displayed. You might as well set the background color to white, too. The background color doesn’t print anyway.
I see you have the focal length set kind of long (narrow field of view). I shortened it up to something more appropriate. I get the sky going all the way across the page, then.
It’s interesting, though. In your screen shot it looks like you have the model window set to be a vertical rectangle instead of horizontal. I can get a similar result if I drag the tray way out to make the model space narrow.
Here I’ve edited the style to get rid of the sky and set the background color to white. Then I adjusted the model window size so it more closely matches the aspect ratio of the paper.
You could get much better looking results if you were to set up scenes in the SketchUp model and then send to LayOut and render the viewport(s) as Vector. Then either print directly or export a PDF and print that.
It wouldn’t hurt to get in the habit of purging unused stuff from your model. I did and got rid of this:
Reduced the file size by 25%.
Keep on top of the back faces. There shouldn’t be any exposed back faces and you could benefit by using groups and components for the geometry in your model.