D.E., do you by any chance know how to turn off all tesla lights, inside and outside (even when opening doors), in order to drive in or out of an observatory area?
There will be a fuse box, you might be able to pull the fuses associated with the lights.
You can get there an hour or more before astronomical darkness. Then the problem is leaving, and opening the car door. Otherwise you can park a good distance away and hike in.
You can apply opaque tape over every light. Or there is a deep red filter material made for theater spot lights. Something similar is often sold at star parties, people use it to cover computer screens. There is a deep gray window film, 95% opaque so only 5% of the light gets through. I used to use two layers to cut almost all light from devices such as cell phone screens. That is fairly cheap, I used to get it at Walmart. I would think 3 layers over headlights should do it. Then there is the option of aluminum foil. Plastic electrical tape is good for blocking light. Foil and tape would make external lights dark temporarily.
I had an old van I took to star parties. I replaced the interior lights with red LED lights.
I'm sure you can render your Tesla dark site friendly but it will take some preparation.