Yes, forget about the external drive for the time being and delete stuff from your drive until you have 8-10 GB free, you are going to run into stability problems. Then get an external drive. I have had very good luck with Western Digital, WIth prices being as low as they are, I would lean toward a 1TB drive, they are in the $100 range.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.