AutoCAD Inventor :: Printing Drawings At High Resolution?

We have created a complex Inventor drawing (Inventor 2013) of a very large plant item which we need to print at about 2AO to put up on a wall for training use. We want to create a high resolution PDF file of the drawing first and then print the PDF having checked the quality and resolution in Acrobat Reader.

We have tried exporting to PDF but we found that the colour shaded fills, behind the lines, are too compressed and the resolution very poor. We tried increasing the paper size but this did not work.We have tried creating a plot file by printing to file using the driver of a large roll feed plotter and then creating a PDF from the resulting file. This was a little more successful but still a long way short of the resolution or line quality we require. When you zoom in the curved lines are very jagged and the colour fill still not good.

We tried printing to a generic Postscript driver but this was even worse as we didn't have enough control over paper size or resolution.