Hotel at the airport is the Airways Hotel. Security is OK. Cost about 90 to 100 AUD a night. If you want to stay in town, Crown Plaza is good, similar price to airways, and from all reports Ella Beach is OK.
At Rabaul, most of the hotels are now at Kokapo. Kokapo Village resort is OK, security OK, similar price to Airways. Also Brian and Bev Martin have a place that is supposed to be good, halfway between airport and Kokapo, can't remeber the name.
Rabaul, 50 kms from airport has Hamamas and Kaivuna, both OK but dusty. Kaivuna is about the only building left standing at that end of town (if it's still there). It was good when Brian and Bev ran it a few years ago, not sure now.
Remember, hotel security is pretty good, but be on your toes if you are walking around.
Airways and Crown Plaza have Airport buses, as does the Kokapo village.
Beware of the crappy taxis, new ones that are OK are Scarlet taxis and Red Dot.
Plenty of places to visit in Rabaul, mostly relics of the war. Sub base, hospital caves etc. Won't be hard to find somebody to show you around for a few bucks.
Places to visit in Moresby, hmmmm. I leave that to somebody else. Botanic gardens, good carvings at PNG artifacts if your into that. Security outside hotels in Moresby is not that great.