I guess all this extends beyond my knowledge base. I think I see two issues that apply whether I'm home or driving.
One: what device is most convenient. I was very happy in the old days with books on tape and my Walkman. The CDs aren't convenient at home but do work well in the car. Playing a CD at home means on my stereo which is in the living room with speakers on the wall, but that's not a good way for me to listen. A tablet works fine at home for digital (downloaded) books, but not good in car because there is no place to put it and I can't hear it over the road noise and AC fan in the car.
Someone asked about bluetooth...I have a Bluetooth speaker I can use in the house, but there wouldn't be a secure way to use it in the car. Is the idea that some car audio systems pick up Bluetooth signals from devices inside the car? I don't think my car is that fancy. I have a 2010 Toyota 4-Runner (basic model).
So this is the second issue: how to hear in a car. There is something Bluetooth in the car in that a cell phone can connect and then the conversation goes through a speaker, but not through the radio's speakers.
(Taking a break in this diatribe to go to car to get manual and see if there is a feature I have never been made aware of. I shall return as I would appreciate advice on what I should purchase to accomplish my goals)