Is there any way we could get a better quality manual? Something with a greater resolution that is easier to read, maybe including the front and back cover too?

Yes, the manual is a bit difficult to read.

I was able to find to very nice copies of the manual and reference card online.

This is a nearly pristine scan of the Amiga manual:

http://oagd.net/amiga/rocket-ranger/files

And this is an equally pristine copy of the Commodore 64 reference card (which works perfectly fine for the Amiga version):

[url=ftp://8bitfiles.net/cbm8bits/c64/game-manuals/Rocket_Ranger_Operating_Instructions.pdf]ftp://8bitfiles.net/cbm8bits/c64/game-manuals/Rocket_Ranger_Operating_Instructions.pdf[/url]

Half the pleasure of these classic games is the wonderful documentation. It's a shame that pristine copies of the original documents is usually an afterthought with these releases.