I didn't find a reliable way of converting absolute character positions into TextPosition instances.
I had exact similar problem, I found out that there is a bug in RichTextBox because it does not count "new line characters - \r\n", so as your line numbers increase, you will find that your offset is positioned wrong by line number count, and I had solved my problems by offsetting line number from offset.
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.