For those of you using Garmin Basecamp (other route planning tools are available!),
you can create a file of the waypoints from Google Maps by following these steps
first, click the '3 dots' next to Waypoints and select 'Export data'
and choose the KML/KMZ option
then choose 'Export as KML' and save the file
Now you can use the File -> Import function in Basecamp to load the waypoints to a list.
If you're using another app,
free free to email some brief instructions or the function to use to wpc20xx@gmail.com
& I'll add them here.