Originally Posted by Atlas Shrugged

If you feel more comfortable with paper maps it’s all good, ensure you get a set of detailed high resolution maps such as the Michelin maps for France however I haven’t used a paper map in 20 years. I use google maps for verification of a route built with proper routing software, street view is amazing and transformative, but I would never use google for route building. My route builder of choice is RideWithGPS but I also use Komoot both are excellent and the annual price is negligible in the big scheme of things. Both of the above export the routes directly into your GPS device. Most importantly RideWithGPS has a heat map feature showing the roads most frequented by cyclists in the area further validating the route build. This method has guided me all through Europe, Vietnam, India and most regions of the US.

As previously mentioned I would build the trip around the regions and towns you wish to see. This is a highly personalized endeavor and need to find what works for you and your interests. I avoid tourist zones such as the Algarve like the plague and loved the upper Douro or Tras os Montes.