Hello @JamesC Thanks for reaching out.
For Live Map, you are not required to have data to use the feature. However, you will get best results with data due to the fact that it syncs to your mobile device after it has completed, using your data. The bandwidth is not much, about 8MB. If absolutely necessary, you can fly the Live Map offline but it will affect the quality of your experience.
As far as card readers, I would recommend a powered hub that can connect to your iPad.