The radio on would be a pretty minor draw on the battery but the blower would really suck the juice. I live in MN too and those mosquitos are bad stuff. Spray really does nothing and they will eat you alive. If you are really set on the drive in you could try to pick up some fabric screen from the home depot and put it over the windows then you could leave them open lol. If you draped the screen across the door and closed it the only seam would be at the bottom where it hits the door panel. The door seal would hold the other 3 sides. Just an idea, either that or go to an inside movie lol. I know the drive in is an experience in itself though.