I might be one of the lone dissenters here then, LOL (depending on how we look at it.) I enjoy using pre-written adventures because they serve as a really nice backbone of an entire campaign arc. Now that being said... I also do not really run the adventures as they are in the books, following the story from point to point, just "reading along" as it were. I use the adventures as the spine of the story and then find anything and everything I can in other modules and books that are close to how the story goes to populate all the surrounding areas with like-minded side plots or additional details. For Curse of Strahd for example that meant stripmining Return To Castle Ravenloft for parts, the 4E module Fair Barovia! had parts I inserted into the campaign, and I read through a whole host of 2E Ravenloft Campaign Setting material to have at my fingertips for ideas should they be necessary.
What that does is allow me to have a pseudo-sandbox available when necessary if the players veer off the beaten path of the main storyline... but everything out there still constrains the world and feeds back into it. The players might decide to forsake the main breadcrumb and go do X... but because I know what the over-arching storyline of the campaign is and know all the bits and pieces of all the adventure parts I've collected that I've already run the red yarn to (It's Always Sunny meme-style)... I can improvise organic connections that can circle the group back around towards the main story from wherever they have wandered off too. And almost always those connections are more than intriguing enough that they will pick up those breadcrumbs on their own (and not feel as though I'm "railroading" them.)
Just because my Ticket To Ride train ticket might say 'New York To Los Angeles', it doesn't mean there's only a single track to get there. Which is why I gather as much additional material over and above the pre-written adventure as I can, so that I can lay down that track in 75 different configurations depending on the whims of the player's interests. But at the end of the day I'm still using the plotline of the adventure book as the narrative outline, because I find it results in deeper and more involved stories than just laying down random encounter track after random encounter track in front of the train in hopes that it just creates a satisfying narrative after the fact.
What that does is allow me to have a pseudo-sandbox available when necessary if the players veer off the beaten path of the main storyline... but everything out there still constrains the world and feeds back into it. The players might decide to forsake the main breadcrumb and go do X... but because I know what the over-arching storyline of the campaign is and know all the bits and pieces of all the adventure parts I've collected that I've already run the red yarn to (It's Always Sunny meme-style)... I can improvise organic connections that can circle the group back around towards the main story from wherever they have wandered off too. And almost always those connections are more than intriguing enough that they will pick up those breadcrumbs on their own (and not feel as though I'm "railroading" them.)
Just because my Ticket To Ride train ticket might say 'New York To Los Angeles', it doesn't mean there's only a single track to get there. Which is why I gather as much additional material over and above the pre-written adventure as I can, so that I can lay down that track in 75 different configurations depending on the whims of the player's interests. But at the end of the day I'm still using the plotline of the adventure book as the narrative outline, because I find it results in deeper and more involved stories than just laying down random encounter track after random encounter track in front of the train in hopes that it just creates a satisfying narrative after the fact.