All roads here consist of pea gravel. That is loose gravel the size of a pea. This pea gravel can be ankle deep. And it is slippery as hell. The Munda Biddi trails has descents that are so steep that I could hardly walk my bike down there. Combine that with loose pea gravel and ruts as deep as the Grand Canyon and you are up for a trip to hell. I realized after 2 minutes that the only way to enjoy that bloody track is to be an 18 year old hard core mountain bike freak wanting to prove his manhood on a mountain bike with 5 kg suspensions and no panniers at all. If you are a more mature female with a sort of disturbed sense of equilibrium, no imminent death wish and panniers on your back wheel this is not the trail for you.
I decided to do "Munda Biddi light" and go around it on dirt roads just using the Munda Biddi shelters. I bought what thought would be a good map and set off. I soon had to realize that pea gravel is not a Munda Biddi phenomenom - it is everywhere. Cycling on bitumen I usually do between 15 to 20 km/hour. On pea gravel you are lucky to do 6 - 8 km/hour. 40 C heat is not very helpful there either.
I did not bring a GPS assuming that there would be road signs. No such luck. There seems to be an Australian law that forbids road sign on dirt roads. And because this is Western Australia (it has the size of Europe with a population of 2.2 million) there is no traffic either, e.g. no one you could ask for directions. And if you assume your map is right you are wrong again. My map (2008 edition) showed all sorts of roads - some of which did not exist at all.
As you can see, I was having a great time and a wonderful adventure. But there is a happy ending: I survived without any serious injuries, dehydration or snake bites.