I ended up getting a small portable heat pump. I've used for almost a year now and it has been the perfect solution for me. It calls the van down in minutes. It is a heat pump wit an auto mode that hold a temp. Had a hot night this past fall and front came through. Went to steep with the AC running and woke up with it in heat mode.
The unit fits perfectly between the front seats and is the perfect height to double as an elbow rest when I'm driving.
These are about $250 from the box store and it has a remote so I don't have to get up to change the settings.


I just run the vent out the window and seal with a few pieces of foam and a plastic sheet closed in the door to keep the rain out.
