I sleep in my car now and always get water on the black part of the top of the windows as well as the windshield and the plastic dome light covers.

I have those window cover things on all 4 windows and it helped a little but the problem still remains. It's been 30f-40f out. The cold isn't an issue for me but the moisture is. Mostly how annoying it is to remove the water before the work commute.

I ordered a few cross flow fans (6", 8", 12") and I also have a bunch of 120mm, 140mm, and 200mm computer fans (all 12v)

any suggestions on best fan positioning for optimal air flow/condensation reduction?

 

The moisture is coming from your warm body and your exhalation during breathing. When this warm moist air hits cold surfaces, it condenses since cold air holds less moisture.

The best flow would be across your body and out the car. Unfortunately, there are no openable windows on the rear quarter or liftgate. The best you can do is flow across the rear door windows to try and vent as much moisture as possible. If you are sleeping with your head at the front, this might work.

Steve