I was pretty sure I knew how to do this, then I saw a video online where someone explained it a bit differently.
When I trample, I just pick a direction, and go SPD + 3" that way. I get all of that, attacking small models I pass over, et cetera.
My issue is with the wording at the end. I have to have room for my base. It's been my understanding that this means I have to fully pass over everything, and have room for my entire base without overlapping anyone.
In the video I watched, they used the path of least disturbance to move models at the end to make room for their model.
Obviously this makes a massive difference. If you need room to make it all the way over, models like the War Wagon are potentially very devastating, but only if there's a lot of room to move. If everything moves around you, it makes trampling a lot easier.
So am I right, or is the video right? Or are we both wrong, haha.