My 2014 Outlander had terrible road noise. Insulated the whole back area up to the back of the front seat. No noticeable difference.
Then I insulated the hood with foam and Kilmat in some sections. See photo.
Insulated the wheel well covers with Kilmat and up under the fenders with 3/8 inch exercise matting glued on with liquid nails . I also packed the area facing the front doors. One photo shows the skimp factory wheel insulation

Hood foamed and low spots filled with Kilmat

3/8 inch material I got at Harbor Freight. Was a mat for floor or knee protection

Flimsy factory insulation on wheel well covers

Kilmat on wheel well covers

Complete back end insulated. No big change

3/8 inch material on skin of fender with liquid nails

Installing Kilmat inside the doors and some areas on the surface was the biggest noise killer. Door panels was surprisingly easy to get off and back on. I recommend starting on the front passengers door to start as a learning curve.
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Moved on to installing Kilmat in all four doors inside the door and on the outside surface that made a tinny sound when tapping.
This is like driving a new car ! The noise reduction is amazing. And I still have the original tires on it with 32,000 miles.,

 

I can verify that sound deadening the doors make a large improvement in two counts: road noise and audio performance. I did it in my Outlander Sport/RVR few years ago. In the link below one can see a DIY video how to do it.
Sound deadening

 

My biggest area of noise seems to be from the engine compartment. I have a 2014 SE 2wd 2.4L. I've noticed on newer models there is a mat of deadener on the upper firewall that mine doesn't have. I am going to do the doors

 

Hi Christopher, nice job! I did the same thing overall, except the hood. I even did the roof. I also have 2014 SE 2.4 and you are right, the engine is very noisy. It's those lifters! Did insulating the hood really help??