Real world and GPX import

Hi there,
After fews years without being close to unity, I'm back ...
I looking for some answers to my questions.
For the first one : what is the better solution to import real geo postions from the real world into my unity scene ... like a terrain ? On google I found some good stuff like mapbox etc but I want your expertise for the better solution before launching my project.
And then, how it is possible/better solution to import GPX or KML files to reproduce some "tracks" into my unity terrain ?
Like I said, I found some stuff on google but I'm not very comfortable to choose the good solution so I need some help and opinions.

Thx,
QR.