Any updates on this.
But first, dvice: if you are using Google Maps, download the maps for wherever you might be, at a place with good WiFi. Then it will work without any cellular signal. However, I don't think you can do that except using the Google Maps app on a mobile device. And, the user interface to do it is clunky - you can only do it a bit at a time, an area defined by a rectangle whose maximum size seems to be about 150mi by 75mi. You can download multiple of these, but doing it so you are sure they will overlap is tricky. And, you have to do them one at a time. Plus they expire after a period of time (don't remember how long).
Anyway...
Street Atlas is getting long in tooth.
Plus, I'd prefer to use something on the MacBook native, rather than having to run Windoze in.a Virtual Machine.
That said, in the past, I used a USB connected GPS to a MacBook, Windows in a VMWare Virtual Machine on the map, GpsGate (to send GPS data to multiple apps), Delorme and GR3 (and in the past Mobile ThreatNet which I'm not going to use this year - too much cost, flaky software (okay, some years ago), would have to buy new hardware.
Now I notice my GpsGate doesn't start any more - probably have to buy a new one (GpsGate Splitter - $40) if I'm gonna be using Windoze.
I've been messing around with MacOS Apple Maps, and Google Maps on MacOS. No joy - won't get data from GPS. Google Earth will, but Google Earth is not that critical, compared to something with Street Maps sort of functionality (and excellent display colors).