You can solder short headers into the bottom of the Intel mini-breakout board. Then you can use breadboarding wires to connect to peripherals or to a prototyping board. They expose pin rows J17-J20 rows 1-14. The pinouts themselves are listed in the Edison Breakout Board Hardware Guide_331190-003.pdf pp 7-8.
You can access the pins directly via the mraa library from C/C++, Python, or NodeJS:
- mraa source, examples, and docs: intel-iot-devkit/mraa · GitHub
- Breakout board pin codes via MRAA: mraa/edison.md at master · intel-iot-devkit/mraa · GitHub
If you'd rather not mess with the Intel board, Sparkfun has a breakout board coming out (Intel® Edison Block - GPIO - DEV-13038 - SparkFun Electronics) and a few people around these parts have mentioned they are working on their own breakout board designs.