We have 6 dogs, they are the family.
I modified the 01 Sport Trac to accommodate them, canopy on the box with insulation, plywood platform with 2X2 stringers on the floor with carpeting on the box floor and an axillary heater to keep the temperature comfortable. It gets pretty cozy with 3 dogs in the back seat and three in the box.
We get -40 or lower here in during January and February, our dogs go out, do their business, go for a quick run around the yard and then back inside. I can't even imagine leaving the dogs outside in frigid winter weather or the opposite, scorching 95 - 100 F summer.
I love dogs.