Hey Kiki

[GlassWolf]

you cut a hole in the floor or hatch of the vehicle and duct the enclosure to outside air.
not an ideal way to do things, since you have to cut holes in the car that really can't be sealed off from the weather so to speak.
The other option is to make the hatchback or SUV cargo area into a separate enclosure of very large volume, which would pretty much take up the whole trunk space to accomplish making a dual chambered enclosure where one chamber (the large one) would simulate a trunk or open air separated from the other chamber.