Using a TRACK or ROUTE is it possible to create an offline map (download openstreetmap tiles ) on a PC or MAC? Then transfer to a phone via USB?

Or is the ‘create offline map’ mode only only possible using the Viewranger phone app over wifi?

You can copy purchased maps via USB but I’m not sure about free ones. Drop them an email they are always quick to respond.

Have a look at Orux maps – it’s a bit fiddly to get used to, as it’s a Spanish made app and the English manual isn’t great, but it’s really useful for creating offline maps on phones/tablets. Should work with openstreetmaps.