I am hoping to use the ATMega1284P for an upcoming project. I I did not see any way to program it / upload the program from the Arduino IDE: Is it just under my nose and I missed it or is there no way to directly use that chip in our world?
324, 664, and 1284 are all supported in Arduino IDE for some versions now, you shouldn't need to modify file if you have recent version that shows under board setting these chips.
EDIT: used wrong image, it was for programming 328 not 1284