Wow, this sounds a great idea and a massive challenge in Australia. Reminds me of last summer's holidays: Perth > Sydney > Brisbane > Cairns > Brisbane... then back to Scotland via Singapore. Ah, just memories now.
Anyway, some thoughts
1) Make sure the baton is waterproof or the detailed records of handovers and locations could be damaged... oh, forgot you're not doing this round the UK!
2) Perhaps this topic could show who has the baton, not just where it is.
3) In between handovers, could the current holder take the baton everywhere they ride, and track these routes on the map somehow?
4) Has the map been started and is there a link to the map?
5) I do a bit of riding around Scotland with work. Anyone in UK fancy this idea? Ok, for the pedants out there, I really mean Great Britain primarily i.e. the biggest single land mass in the British Isles. Should be fairly easy to include other parts such as Isle Of Man, Ireland (both countries), Inner and Outer Hebrides, Arran, Cumbrae, etc etc.