dnd 3.5e – All about trampling

This answer is an extension of a discussion on the subject. You may be able to better understand the question by answering this question.

I am interested in a step-by-step explanation of how the trampling special abilities work with a reasonable focus on the opportunity attacks against a tramp. It sounds easy at first, but I expect a high quality response to consider possible solutions and in-depth analysis of questionable elements, either. Think of such things as reach, clever positioning possible by stomping on the creature's enemies, moving to places never seen before (around a corner), etc. However, do not limit yourself to answering these problems. I may miss some things that can become tricky when they are associated with trampling.

I agree with any fairly standard monster as an example. This may very well be a triceratops if you need a starting point. He then tramples several enemies with one action.