SouthernAtHeart:
GREAT! SO I can write my sketch and use my UNO as the ISP and load the hex directly on the board.
How???
In the IDE, see File > Examples > ArduinoISP. There's tons of forum threads on it, also check the main Arduino web site. I haven't ever actually used it, I just got a dedicated ICSP programmer instead. For $20 or so, money very well spent IMHO. Better to have a dedicated device.
I see in the Arduino IDE
there is Tools/Programmer/Arduino as IDE. Surely it's not as simple as selecting that, and it dumps my Arduino sketch, converted to hex code straight thru the UNO, unto the motor board??? That would be great!
Correct. The Arduino has to be running the ArduinoISP sketch. No bootloader required on the target chip.