As our cargo van is reaching the end of its useful life (for us) I have been researching for our next TV. For past 2-3 years I have been focused on a
Rockport Cargoport body on a GM 3500 dual wheel chassis. I would order the "box" with rear heat, AC, and a powered vent for environmental control for the crated dogs. The "box" would also include a sliding pass-through door from the cab so we can monitor the dogs in transit and a curbside door for easy access when hitched to our TT.
We don't need the passenger space, we need the cargo space for crated dogs.