You can also use papercrop to crop the .. paper
Since it's a scanned document you'll have to define the crop areas yourself, which will be very easy if all pages look approximately the same. It can also split the document in many smaller documents in case the file is too big for your ereader.
If you want to read it like this, probably Kindle DX is your way to go.
Try resizing the image to 800x600 and then enlarge it in the most crappy way until it's as big as the screen of your reader (I believe the Nook is around 20 x 13 cm). If it's readable like that, then you can use kindle, nook, whatever. Do the same with the dimensions of the Kindle DX.
With such a small font and big margins, though, you may be out of luck even with the Kindle DX.
Cropping the pdf still looks like a must to me.