A lot of information for dealing with the problem on an immediate temporary basis. I've been riding bicycles for racing and daily transportation for several decades. I did get use to the cars and close passes for a while but after several friends and acquaintances killed and experiencing a few near misses myself including a couple of trips to the hospital in an ambulance I'm no longer as comfortable. We have zero protection when we share the road with cars. It only takes a brief moment of distraction for a driver to kill us. What is a very minor fender-bender between two cars can easily be death, major injury or disability for a bicycle rider in the same incident.
Longer term you need to talk to your city and county about making this road safer and better for all users. It sounds like at a minimum it should have a 10' wide MUP on each side with appropriately designed junctions (see CROW Bicycle Traffic Design Manual and MassDOT Bicycle Guide
MassDOT?s New Bikeway Guide is the Beginning of Good Things | streets.mn).
Ideally though it should likely have a protected bikeway on each side as well as a sidewalk (both designed to CROW or MassDOT standards). Don't you wish someone had come along 10 years ago and fought for that so you'd have it today?