I got pretty lucky and located a universal AC/DC adapter I already owned. It works perfectly for the A-ONE, which requires 12V and a 2.1 mm barrel connector. I connected a PS/2 keyboard I got with an old HP computer I bought a few years ago to play PC games. Finally, I connected the composite video from the A-ONE to a Pinnacle USB HD TV tuner I already owned (I was going to use my El Gato EyeTV Hybrid, but I couldn't find the composite cable for it.). Fortunately, the EyeTV software recognizes the Pinnacle tuner.
I applied power and got the startup screen to display on my MacBook Air:
After pressing the RESET button, you're dropped into the Woz Monitor where I invoked WOZ BASIC by typing E000R. WOZ Basic is stored in ROM from $E000 to $EFFF. I wasted no time writing my first program in WOZ BASIC:
I played around a bit more and memories of AppleSoft BASIC came rushing back!
The next task will be to explore some of the items on the CD-ROM and look into connecting to the A-ONE via the serial port.