Remember that a 75 lb dog will weigh several hundred lbs if you ran into something and it was "launched" into the netting. Design it so that you have padding across the "floor" of Dog World with storage for the ramp and other items under that and the padding extends UP at the front just about to the dog's chest. That way if the dog is laying down and you hit the brakes it will slide forward into the padding and not the back of the seat or pass through towards the dash if you have Captain's chairs up front with a console storage bin.
Maybe use the netting as a last resort and rely on a flat cushion for your BF to sit, rest, lie down on and extend some cushion up the back of both seats up front so there is that "snout sniffing" and place for your BF to check you and the happy highway out as you roll down the road.
I would still think about the harness set up that attaches to the seat belt in the pass seat for when you get off the highway and are going slow on the way to your camping spot...letting your BF relieve him/her self when you get off the major road and then get to ride up front with the window down would make them and you...happy campers.
My 1988 F-250 HD 4x4 XLT Lariat has no third door, it has a bench seat in the back that folds flat and has two captain's chair with a center console between them. You access the rear by tipping the pass seat forward. What kind of a set up does your F-250 have?
How have you figured out to get your BF into the camper and into the truck; use the same ramp? How does it get attached to either one or is it free standing?