It wasn't as far as you may think. I believe I read they walked just over a mile but there is no way to stop horses from pooping but the street cleaners likely follow after or at least that's how most cities handle parades.
It seemed like a decent sized procession but I don't think it would have been large enough to shake the ground. It is my understanding that there was small representation of each division but nothing huge.
I realize that this is part of her job but I feel she would have rather had a funeral similar to her husband, who died during a covid outbreak and was small and intimate.