Great questions. I'm hoping you get great answers.
I know experienced cyclists seem less concerned than I am. I rode today with two people who went down busy roads I'd never ride. We lived, but holy cow, I was concerned. (It did make me faster though ...)
I think the old "familiarity breeds contempt" comes into play here. Maybe riding in a group at leat makes you more visible.
+1 on find a local club and rid ewith them.