Offline 2nd layer easy download?

[Sam uel]

Hello all,

I'm seeking the web about preparing my trip in offline as i'll not have connection for 2 weeks. For the OpenTopoMap main layer it's easy in the map download menu.

But what about the 2nd layer displayed from an external public source for slopes map? Downloading tool with a long touch is not super easy to use and downloading too much information as the selection box is horizontal and not always sticking to your GPX track.

Thus, i'm looking for the easiest way to download my map layer around my GPX along 14 days of backcountry skiing? Any idea?

In parallel, by passing through the track manually, everything is going to cache tiles but i've no clue about cache size and duration? Any info there as well? It could be a kinf of workaround.

Thx by advance for the help.