A good website to use to start to plan a trip to Australia will be the Australian Tourist board website. This gives loads of information on the sights and good places to visit.
buen viaje
Trevlig resa
"Maligayang paglalakbay"
maligayang paglalakbay
You could say "Habe iter jucundum!" (literally: "Have a pleasant trip/journey!")
bon voyage, good trip, good journey. as in 'have a good trip'
As Australia uses the English language (with an Austrian twang) I would simply say, "Good night."
"bon voyage en France" is the way French speakers would say 'have a good trip to France'.
cael trip da
They say 'Schoene Reise', which translates to have a good trip.
You say "Good bye" in Yoruba language of the Western African origin as "Od'abo".