I went ahead and did what I had to do! I didn't really care what the inside of the WD cabinet looked like as it would be covered up anyway and looks a little ugly. It was quick with a Dremel. Here's the interior.
As you can see the first location didn't work as there was part of the aluminum structure in the way. I then lowered it and checked to make sure nothing else was in the way, measured again and had to move over a little to avoid hitting the trim on the exterior. Drilled a small hole through the exterior and double checked that vent would hit anything out there.
And the exterior -
The exterior dryer vent was white from Lowes and I had some Dark Rubbed Metallic Bronze spray paint that matches the Cougar's bottom skirt perfectly.
I sent Keystone an email asking to clarify their instructions and they told me to take the unit to an authorized dealer to do the work and sent me a copy of their warranty. I didn't expect anything different.