Hello fellow tourers :)
I have been working with Boom Festival officials on a guide to help people cycle to the festival.
You will find the reference in page 2: http://www.boomfestival.org/boom2014/site/pdf/boomfest_bybike_initiative_supportGuide.pdf
This year, about 100 peoples made it to the festival by bike! This number keeps growing with each edition. Stay tuned for 2016!
Take care. Peace,