I found a couple of cargo nets the work well in the interior for stowing light cargo against the ceiling of my 710K. I assume they would work just as well for any K-model. Both were pretty inexpensive...
My visors were becoming overloaded with beanies, sunglasses and baseball caps, often dumping them in my lap while on the trail. This small net fit the ceiling space between the front seats perfectly and stows adequate sun gear for 2 people...
Rig Rite 1150 Boat Console Cargo Net - 10" x 20" on Amazon
Granted, I do have an elevated roof in the back of my 710K, but I think this net would still function very well in an unmodified truck. We use it for stowing jackets and clothing when sleeping in the back...
MICTUNING Upgraded 41 x 30 Inch Cargo Net Auto Trunk Rear Cargo Organizer Elastic Mesh Net Holder - Universal Fit for SUV Truck Mini Vans on Amazon