jgsugden
Legend
If you have a story situation where it makes sense for the villain to have hidden the pivotal thing behind a secret door, nd you fear that if the PCs do not find it the game will be disrupted - consider letting them fail, and then provide an alternate route that allows the PCs to get back on track, but perhaps at a small cost. It might be a journal entry that hints at the door location if the PCs buy the book, an NPC that is willing to give up the location of the door for a price, etc... Or, it might be someone else getting behind the door and acquiring the McGuffin and the PCs needing to chase the NPC. We don't want any secret door to be an absolute game stopper, but unless there is an overwhelming time pressure involved, it is rare that you can't have an alternate path available.
On a personal basis - As a DM, I create adventures agnostic to the party. I occasionally add something as a frill that 'only the PCs could do' to make them feel special, but for the most part, the adventure doesn't worry about what they can do. Players often come up with solutions I did not imagine when faced with a problem I place before them, and there are times when they fail in their mission. All of that can be used to tell good stories. There is nothing wrong with the PCs failing sometimes - as failure is one way to keep the stakes high.
On a personal basis - As a DM, I create adventures agnostic to the party. I occasionally add something as a frill that 'only the PCs could do' to make them feel special, but for the most part, the adventure doesn't worry about what they can do. Players often come up with solutions I did not imagine when faced with a problem I place before them, and there are times when they fail in their mission. All of that can be used to tell good stories. There is nothing wrong with the PCs failing sometimes - as failure is one way to keep the stakes high.