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I used a Breakfast-in-bed style table with the legs folded away. It just so happened to fit perfectly in the passenger seat. The right side rests on the door, and the left side was supported by a rolled up windshield shade. As long as the arm rests were down it was pretty stable. Everything could be put away easily when it was time to roll, but it wasn't perfect. if you needed to get up you risk the table falling over.
I'm sure there's better solutions out there, but I already had the table for using a previous laptop in bed.
It's been a while but I'm pretty sure this is it: https://www.amazon.com/NNEWVANTE-Foldable-Adjustable-Breakfast-25-6x17-7in/dp/B0749FSVSJ/ref=sr_1_101?crid=34AZBJXK57WJA&keywords=bed%2Btable&qid=1649027201&sprefix=bed%2Btable%2Caps%2C112&sr=8-101&th=1
Truck was a Freightliner cascadia 2019