Stuck is stuck. If the bent metal isn’t going to allow the door to move, the weight of the door doesn’t matter.

It’s not uncommon for doors to be inoperable after an impact. This goes for all kinds of doors - even normal manual ones.

Certain of his books are really, really good. Others were written during cocaine and alcohol-fueled binges (Cujo, Tommyknockers) that they really don’t hold up well. King apparently doesn’t remember writing Cujo, since he was blackout drunk during most of the writing process.