Sketchup does provide an isometric rendering mode as well. Turn that on and set the camera to one of the three default views (straight down) and all perspective is eliminated
And in answer to the question on pdf, I have been using cutepdf. Like the one mentioned it sets itself up as a printer driver (used the ghostscript libraries). I know the page can bet set all the way up to a 36"x96" pdf.
-Rob A>