Wow, you've built a beautiful headbud there. Unusual calyx to leaf ratio for an outdoor plant.
I would check the weather report first for the time you'll be away. Humidity is a welcome foundation for mildew or bud rot in that condition.
Then it's the old game with the microscope and the color of the trichomes, which (for us hobby gardeners) gives the most accurate indication of ripeness (little clear, mostly milky, amber depending on the desired high).
From what I can see, I would harvest before you leave. The calyxes are fully matured, (without a microscope) I would guess that they will be overripe in 10 days.