Going by the replies you've already got, mostly obviously from people who have never visited, I wouldnt go.

Its a few years since I last visited Papua New Guinea, but I think most of what I'm about to tell you probably still applies.
Over a period of about 3-4 years I visited about every 2 months on 10-12 day Sales trips. I was alone during my travels, in a rental car and occasionally carried quite a bit of cash (kina).
All 9 stone of me, with specs and natty tropical shirt and shorts. I was healthily frightened for much of the time but only once got held up for a 'toll' by a tribe of villagers on the main highway up to Mt Hagen. Another time, a nutter sleeping under my car tried to slice my feet off with a parang when I inadvertently woke him in the morning as I set out on my rounds. But he missed, I lived to tell the tale.
Ive a few other stories that I might include in my memoirs one day but thats enough for now.

My trips usually included the main centres like Port Moresby, Hanuabada, Mt Hagen, Goroka, Lae, Madang, Mende, Arawa, Rabaul, Kimbe, Bougainville but also some of the smaller towns that had big Trade Stores (who were our customers).
In most big cities and towns your accommodation and food at the hotels will be excellent. (for instance the Bird of Paradise in POM was built for a Royal visit of the Queen of England I recall). Lae Lodge was a favourite. Service great and comfy beds. (will depend of course on the price you've paid and the 'standard' of hotel your tour provides. Check out each on the web before parting with your dosh.)

Your first visit will be an eye opener. There are over 600 languages spoken in PNG. Called Place Talk. Most speak Pigin English (this is a language with its own dictionary by the way) and many speak English (or American ). When I was last there, the Summer Institute of Linguistics (an American crowd), was still translating all 600+ languages into English. Nice people and their 'shop' was a customer of mine
At any one time there are 'village wars' going on all over the country due to a village tradition called 'payback'. Some of these 'wars' are so old they cant remember why they are fighting. I can almost guarantee you wont see one, tho you might be lucky. )

PNG people, in the main, are a fantastic race of people and you are very fortunate to be able to be able to plan a trip. Think of a primitive South Africa. The expats (white people), who live in PNG are referenced by category: One of the 'M's'.. Mysteries, Mercenaries or Misfits. I will leave it to your judgement of what I was.

The best advice I can give you:
Is make sure you are well dosed up with anti malarial tablets (that's the only precaution I ever took and never caught any disease).
As a 'newbie' to PNG, stay with your group. You will be as safe in PNG as in any other 3rd world country.
There are no criminals in PNG, the bad guys, and there are some really bad guys, are called..Rascals. Cute.
Never, never, ever look into the eyes of a PNG born person. Regardless of temptation. Just dont! It may be taken as a challenge if you do and you will be unlikely to win. If challenged for any reason: walk away, dont look back. He or she will have friends nearby, more than you have.
Never ever try and surreptitiously photograph a local with red eyes, red gums who is spitting red stuff (buai). I speak with experience.
Hopefully your guide is well experienced in PNG customs. Follow his (hopefully, not a her), lead without question.
On that matter, always get permission to photograph locals (unless you are a great street photographer and you are 100% unlikely to be seen, even if you are with a group).
Temps can be very hot and humid but cold at night in the Highlands.
I carried my own mosquito net for use at night in bed.
I always drank bottled water or boiled the water in my room and didnt use the ice in the room fridge. Never had a tummy upset.
If you take gifts (I always had them handy when on the road, but not in cities) I would suggest, something like a USA pin or similar. NOT cigarettes (they can cause more trouble than good). By the way, as already mentioned, this is a wealthy country, dont assume the guy or woman in ass grass is destitute, he might be worth more than you, financially speaking. I used to deal with store owners who had shares listed on the NYC stock exchange who looked like they couldnt afford their next meal.

All the other be careful conditions apply, like; dont look both naive and rich. Take a small camera that doesnt have a 15 inch lens etc, though the chance of a one off attack on your gear is reasonably small.
PNG police are quick, armed and ready to shoot bad guys so get out of the road if you sense anything amiss.
Dont be surprised if you see 2 burly policemen with shotguns holding hands. And dont stare, its a village thing.
PNG is a fairly wealthy country and the contradictions will amaze you. You might see a village person in a grass skirt, strange hairstyle and a bone through his nose with the latest iphone. Many will speak at least 3 languages that I mentioned before but some will also speak a few other Place Talks. (Pigin = plice tik from memory).

Having said all that, you are in for an experience of a lifetime. In my opinion PNG is the last true frontier.
If it wasnt for the cost (the exchange rate for NZ$ vs PNG Kina is horrendous and prices in PNG are pretty high) I would have gone back since retiring, just for a visit with my camera.
Here beside me at my home office desk I still have two good luck charms given me on two separate occasions, by chance met locals who thought I was pretty okay. One is a small mask with human hair, the other a small bottle with a special 'something' inside it. Both seemed tostill work for me.
All 9 stone of me, with specs and natty tropical shirt and shorts, back then.
Only had one or two 'near misses' in all the visits I made.

I envy you your opportunity. Cheers..

I have been to PNG. I hope you are going to A SING SING. That is a festival where all the tribes

get together and sing and dance for a few days. Both a closeup and mid range zoom or regular lenses would be helpful.

Make sure you have the proper inoculations and take Malaria tablets...VERY IMPORTANT.

Go to cdc.gov (center for disease control), then click Travelers Health, then click Destinations and click under select one, Papua New Guinea for vaccinations and which malaria meds are recommended for the PAPUA New Guinea.

One other thing. As in any third world country, watch your possessions and stay with your group

You should have a wonderful experience..I know I did.

Larry

I lived therere for three years. It can be dangerous, as in any country some places are more dangerous than others. If your going into a tribe you are a little safer as what happens to you while there reflects on the tribe. Split your cash up in different pockets, when you come to a roadblock you can empty one of your pockets and tell them thats all you have. Just pay attention to whats going on around you

Are you going for a sing sing or one of the highland shows? If thats the case the biggest thing you will probably run into is theft at the show

We did that trip. One of our all time favorites. The Sing Sing in Mt Hagen is amazing. I understand that Goroka is even better. Fascinating even without a Sing Sing. Great scuba I’m told on the coast.

Read a lot before you go. And use common sense. Stick with your guide. People were charming. I showed one group an iPad that had an app with a cat that repeated what was said to it. I told our interpreter to get a native to say something clearly. The cat repeated it and they screamed with laughter. So the cat repeated the laughter. The whole little village wanted to try it. Great experience. We loved it.

In towns, like Mt Hagen, there might be issues, but in the Bush we never felt uncomfortable.

People photography, short lenses. Unless you are birding, which is a challenge.

Looks like the basic advice from the Australian Government is " don't go THERE, bloke"!

Seriously, an armed bodyguard should be considered. Kidnapping for ransom is a big risk.

Health-wise: Malarone daily to prevent malaria. Most of the other nasty mosquito-borne diseases are carried by mosquitoes which bite in the daytime - Zika, Dengue, encephalitis, Chickungunya, etc. Take DEET wipes to use on exposed skin whenever you find mosquitoes around (rural and urban areas) and pre-treat all of your clothes with permethrin, which is a repellent that will prevent mosquitoes from landing on your clothing (and will prevent ticks and mites from climbing up your clothing). You can buy that on Amazon and at Bass Pro SHop. Get a big spray bottle. It has a faint odor when wet but not once it dries, and it will last for 5-6 weeks, through multiple washes. The best mosquito nets are the wider mesh (that breathes) but that has to be treated with permethrin, or else mosquitoes will land on it and climb through an opening.

Get Hep A vaccination (two-shot series, but the first shot offers about 95% protection.).

Do not have sex with any of the locals. There are a lot of STDs there, including HIV.