Why don’t you just let her ride on the seat? That’s where Max rides. If you think that the rear seat of your truck is too narrow (I have a non-functioning F-150 — an older model) you can just place boxes (storage tubs), or coolers, on the floor in front of the seat and cover all with a cushy comforter so the dog can stretch out. We’ve taken our Max coast to coast that way. That way you don’t have the work of removing and re-installing the seat.
She is used to back seat crew cab area. It is one of those four door trucks and the back seat area is big and comfortable. Every once in awhile she will come up and sit in the front seat. She does not stay there long. Every time we go under an overpass she ducks her head. It is funny to watch. The back rest for the back seat does fold down and makes a nice flat area. When Aladdin was alive he grew too tall to stand comfortably on the folded down back rest so I just removed the entire seat and put their dog beds down on the floor. Made for easier entry access for them also.
I have removed the back seat once. It has never been put back in. It is kept in storage.