Arch Mix running Arduino General Questions

I have just started experimenting with the Arch Mix board.
I have updated the bootloader to run Arduino.
I have been able to do the most basic things (Serial connection to PC, and Blink in RGB).

Q1: What pin is the SW2 User Button connected to?
I am trying to use the board’s “user button”. The wiki says it is pin 125 (or as a typo 152). I cannot figure out any other values to try from the schematics.

The following line of code causes a hard crash in setup()
pinMode(125, INPUT_PULLUP);

Q2: What library will give access to the SD card for logging data?

Q3: What library will give access to the real time clock?