Just back from a trip California to Colorado, I learned on my trip to LA that a sleeping bag is not enough padding. I got a 3-inch latex foam pad we use in the RV to make the dinette bed a bit more comfortable and laid it out, covered it with a thick blanket, put in two big pillows and a sleeping bag, brought my bathrobe and towel and I slept great!
Best part was that in the morning I rolled the pad up and flipped up the seats and you couldn't tell I was on a road trip. With all that stuffed in the trunk, I still was able to get into the lower trunk to get things out of my suitcase, or even take out my suitcase when I was at a hotel. Used the frunk for a hamper, had a glorious trip. A little hard getting in enough to swing your feet into the trunk, you have to close the door with your feet.
Yes people did check the car out but I didn't care, potentially there is a photo of my sleeping somewhere on the net. I parked at a rest stop going east and a casino charger going west, where it was HOT, glad I had the power to drive the AC. Should have pre-cooled the trunk, it took some time to dissipate that heat, but the AC turned into heat by the morning. Wish my RV was that smart, I have to get up and flip the switch on the thermostat, while the Tesla just tracked the desired temp. I used an app called Camper to keep the Model 3 HVAC on while the screen was asleep.
Not like the Model S where you can sleep two, but for one it was VERY nice, I am probably too big to share even a Model S, so perfect. If you are following in my footsteps I found a backpack was a great addition, for taking clothes to a restroom to change into PJ's and brush teeth. I tried changing just in my bathrobe while in LA and that was not cool, not taking it next trip.
-Randy