My first step was getting the tiny, and awesome Adafruit Monochrome 128x32 OLED to work with the Leonardo software.
At the top of the code, I have comments showing what OLED pins match up to which pins on the 32u4 breakout.
#define OLED_DC 6 //Atmega32u4 Breakout Pin D7 #define OLED_CS 9 //Atmega32u4 Breakout Pin B5 #define OLED_CLK 5 //Atmega32u4 Breakout Pin C6 #define OLED_MOSI 4 //Atmega32u4 Breakout Pin D4 (Pin on OLED labeled DATA) #define OLED_RESET 8 //Atmega32u4 Breakout Pin B4
//Connect GPS TX to Atmega32u4 Breakout Pin B7 (Leonardo Pin D10) //Connect GPS RX to Atmega32u4 Breakout Pin B6 (Leonardo Pin D11)