My suggestions -
Get some lights for the front and rear.
Get a front rack with a removable bag. (
Link to VO web site)
Consider a larger rear sprocket (wider gear range).
When I toured on a bike, it was all too common for me to arrive after dark. You just never know what will happen. Good lights are expensive but they are small, light weight and actually work.
I have one of those stems and think it is fine.