Thanks so much!!! What I was needing was the control-option B trick. I'd never known about that alternative way of navigating (without the arrow keys). So I now have the OPTION keys paired with B, F, A, and E for navigation, and the COMMAND keys paired with arrow-keys for new columns/rows. Here's a screenshot. What a relief!
Here's my solution. Thanks JMichaelTX!
Numbers navigation Macros.kmmacros (14.2 KB)