My touring has gotten 100X better since detailed electronic maps became available. I can select point A and point B, and get a route that automatically maximizes bike paths and small roads.
Paper maps, good luck. You're going to ride with the cars because that's what the fixed scale printed map shows.
Tour for long enough and paper maps will eventually kill you.
Once you get far enough away from urban areas you run out of bike paths and electricity to power your heavy tablet or computer.
The maps I use (and regular maps) show secondary and dirt roads as well.
One thing I realized this year while riding the shoulder of what I believe is Canada's very first road, is that historically main roads got first pick for the flattest route from A to B. So any other trajectory will necessarily be more hilly and more work. Main roads also have nice freshly paved wide shoulders whereas country lanes have little or no shoulder, rough cracked pavement and a lot of blind hills and curves. Nothing is safe.
And where's the adventure / fun in following a very detailed description of a ride ?