Basecamp Birdseye Imaging Download > 15000 Images

Hi,

I have a Zumo with a 4TB hard drive.  I use the unit on my 4X4 in disconnected off-road travels.  I'm currently working my way from the Mexico/Texas border to Washington/Canada border, most of which is disconnected from wifi.  This route, called the Backcountry Discovery Route (BDR), is a challenging off-road adventure route that requires knowledge of terrain.    I want to download the Birdseye views so I can get a better idea of the next day's travel challenges, but Garmin only allows 1500 images per download.  At that rate, it'd take me a very long time to select all possible routes from Mexico to Canada.  How do I download all BirdsEye views for the US?  FYI - I am using the latest Basecamp software that is installed on a Mac.  The Zumo has a 512GB Micro card installed.