Monermoscoso, you are most welcome. I am grateful to be of help.
A friend of mine and a fellow expat is also a salesman and he travels along the highway to the Highlands region often and there isn't any issues because as you build your relationships, showing courtesy and respect, you will hardly to never come across any problems.
I would suggest that the first few times you travel, go with a local staff member because they'll be able to tell you about places and give you tips or information as you go along.
I haven't heard or read of any recent murders or kidnapping (of expats) although there are a lot of accidents because the roads are not so good and the road rules are not always followed. That just means you'll have to practice good defensive driving and ensure the company gives you a good off road vehicle.
I'm not saying that there aren't any hijackings or roadblocks because this has happened in the past and I have heard a few stories but this is why you'll need to be aware of your surroundings as you travel and as suggested, take a local staff member with you so that they can help you identify red flag areas and also give you tips on how to deal with the locals as well.
Lastly, Lae is a beautiful place and I've met great friends here. If you decide to work here, I'm sure it will be the same for you.
I do wish you well.
Regards,
AS