I should note that I've actually accomplished everything past the read stage with another device. I have a Leonardo that is reading and parsing NMEA sentences from the Adafruit Ultimate GPS Shield, reading some pressure sensors over the I2C bus and some voltages on the analog pins, and then sending everything to the computer in a single sentence once per second. I want to be able to achieve the same thing with the larger weather station. If it matters, it's a Maretron USB100 gateway.