The painting on the wall in the motel
Just before Cooper (?) asks Diane to shut off the light, we can see a painting on the wall.
A desert view.
(probably the Mojave desert where the scene with the high voltage electric poles was filmed).
When they have sex, Diane seems watching this painting just above the bed.
...that's all. No theory about it, but maybe there is something.
BTW the car for "mileage 430" and parked at the motel with Diane is a Ford Galaxy 1963.
Very old car.
"What year is this" under the giant electric poles and at the first motel ?
Had not noticed the rotary phone in both.
I have to rewatch this, but I think the driving scene after consulting Jeffries and leaving Twin Peaks takes place in the 1960's. Diane and Cooper arrive from the future and "replace" Richard and Linda....but we are not watching this happen to Diane and Cooper at this point....we are watching Richard and Linda in the old car. The following morning in the newer motel (new car, etc) we are seeing the ramifications of this switch in the future. Everything is now different, but threads of the past timeline remain.