The TET / Portugal comes through my back yard as does a similar route of off-road, north to south. A lot of guys do the Trans and when they get south do a return route on, what is called, Portugal's Route 66, which is a highway, called the N2, which also runs up the entire country.
A little local jaunt out for guys from the U.K. Steve...
http://www.transeurotrail.org/portugal/
https://www.plotaroute.com/mobile/route/172237
https://www.routeyou.com/en-pt/route...66-of-portugal
It's a big open country with 1000's of tracks, trails and water crossings and right-to-roam, like Scotland. It's just so blumming hot off-roading, unlike Scotland.
I'm sure the links have downloadable gpx files so you can fill your sat nav with all the way points. I have found that my TomTom rider will accept the gpx files but it doesn't have a background map for off roading so I use my old trusty Garmin Csx60. Also Wikiloc is an awesome OS style mapping app.
Also....I wanna drone. The footage is ace!