Rockhampton-Barcaldine-Longreach by bus?

I'm planning to go to Barcaldine and Longreach in the not too distant
future, to see some of the "real" non-commercial, touristy Australia.

I'm in Noosa right now, so when I get to Rockhampton I plan to go to
Longreach and stay there for a little while, by train (it only goes
twice a week apparently), then take a bus back through Barcaldine,
stay there for a little while, and catch another bus back to
Rockhampton where I'll hop on a greyhound/McCafferty's bus with my
existing "hop on/hop off" ticket.

But I'm a little unsure of which buses travel this route
(Longreach-Barcaldine-Rockhampton), and how many times a week/day they
go. Any pointers?


Hallvard