There is a lot to consider. Most Toy Haulers have a much higher tongue weight, so you need a capable truck. Many, if not most, don't have much insulation so that needs to be something you investigate. Check how much air flow gets in the back, again these are garages so some just get enough to take the chill off, you may need a space heater to keep it warm. Putting down carpet can help take the chill off the floor, but that back door can transfer a lot of cold air so you might need to hang carpet or a blanket there.
Two Wire Fox Terriers; Sarge & Sully
2007 Winnebago Sightseer 35J
2020 Jeep Gladiator Rubicon