png help please

I am planning to spend about 18 days in png in september.
I would like to visit the goroka show.
there is so much information about png it is mind boggling.
what are the absolute must see highlights that i could visit in 18 days.
I am interested in visiting tribes,jungle diving,ww2 wrecks.
obviously i may not be able to see everything but should i go independently or try a group tour.
I am an experienced traveller.
what would be the ideal itinerary for 18 days to include goroka show.

Edited by: jasper1889

read my recent post on a month in png - there are others posts on similar trips as well

in 18 days i would suggest rabaul for ww2 and diving, garoka and the highlands and then wewak/sepik