I spent 6 years in New Guinea & Solomon waters, but not on the south coast. New Guinea is fantastic, you could spend years without seeing it all.
The Solomons are even better, with great people.
I did get caught by the edge of a cyclone in the Solomon Sea, down around Woodlark Island, one march, but I think it was the only one in living memory.
I left Cairns, entered in Samarai, & stayed north of there. If I was going again I'd go from Cairns or Townsville across to Honiara, then up through the Solomons, then New Island, New Britain, Manus then Madang
Take lots of
fishing gear & be generous with it, & you'll be very welcome.