David, good input re: a device to hold a phone while driving.
This household has learned that one of the secrets to an almost 50-year marriage is to avoid renting a car, especially when it requires driving on the "other side" of the road from what we are used to. Yep, it is very costly to hire local drivers (when trains, etc. are not easily available), but some things are worth it in the "avoid turning a dream trip into a nightmare" and "keep a marriage happy" departments. But, we realize that may be "just us." Every partnership has different dynamics and every person is different.
But, great advice you offer for those who do drive.
Quick funny story: One time (it was in the Brandywine Valley, my spouse who prides himself on reading a map, and has even from time-to-time in our home state insisted on using just a satellite image of roads/landmarks to find something (oh, the side stories I could tell on how that worked...uh...did not)....but anyway, he made a major wrong turn. His reaction (as he showed signs of frustrations) was: "they moved the road!!!" My calm reply was: "Yes, honey and all the huge trees and historical houses that lined the road."