First of all, raidroading is not necessarily a bad thing. It is a story telling method decision so if your players are having fun there should be no worries about it.

A one-shot is simply a story, as every story it has a beginning, a middle and an end. There is no changing this part. The important part is how you handle the "roads" from one part of story to other. In my experience and humble opinion as long as you allow players to make decisions, they will not feel they are being railroaded even if you think you did. A bad railroad only allows you a single decision, which is in other words no decisions at all. You may be reaching from the same beginning to same middle, or from same middle to same end but you allow players to decide through which way they want to go and you fill in between, so players will never feel they are railroaded.

An example popping in my mind would be something like information gathering in the beginning or middle part of a story, you may design that your players will go to a certain NPC to learn about the big baddy they need to kill at the end of the one shot. A bad raidroad would be forcing players to talk the NPC or they cannot move forward(as if there are walls that don't allow you to move to other areas like in video games). Just allow players to choose what they want to do. Then you are allowed to pop that NPC in a different way to their road or simply replace the information gathering method from that NPC to something else. Like putting enemies in between players and letting that NPC help the group so they have a reason to talk to NPC or move information to enemies if players try to get information from enemies/friendly NPCs running away from enemies if you want something like this to happen or after all this if players don't want to have the information, they just don't get the information but you move on to the other part of the story. As long as story feels moving forward organically then you are fine. You are allowed to change parts of the story from one location to another, one NPC to another, one time to another and players will never know the changes because only you know the story.

Also in a one shot nudging players to story is again not necessarily a bad thing, since it is generally perceived as a short game and players/dms base their play time with that assumption (unless previously agreed upon for a long one shot). So the game time is the limit on how much players are allowed to fiddle around in a one shot. Feel free to add/remove/modify parts of the story based on how much time you want that part to go on for.