Steve - if you call out to the service center they may be able to send you an engineering drawing of the stud placement. I know in the RL there are nostuds behind the area where the dryer goes. Also no wiring, you can place vent wherever it needs to be.
Don't know what you wind up with for washer and dryer but when I cut the hole for ours we went to Walmart and got a piece of foam core poster board. After the shelf was made and dryer ready to go in we taped the board to the back wall, shoved the dryer in fairly hard, and it left a perfect ring on the poster board where the vent outlet was. Took a small square, found center of the hole, drilled through till the pilot bit broke the outer surface. Went outside, covered about a 6x6" area in masking tape and then drilled with the hole saw again from the outside. Worked perfect.
Vaughan & Tracy 2013 RW 36RL, 2013 F350 DRW CC, 2016 Focus. MorRyde IS, MorRyde pinbox, disc brakes, Comfort Ride Hitch. "Life is to be embraced, Grab it with both arms ! "