hong kong then Yangshuo via Guilin 72 hour free visa?

I have 20 hours in Hong Kong next week (no entry permit for Australians I read?, I travel on Australian passport)- then fly to Guilin to head to Yangshao for 2 nights to stay with Australian friends working there. although we will be located in a hotel Yangshuo where the other workers stay - is this ok for 72 hour transit? I don't have tours booked or the "listed hotels" in Guilin.. no travel agent use...am I still eligible?
regards
Hellen