How to structure 2D RPG?

My goal is to write a top-down 2D RPG(Similar to runescape classic, but much simpler) using LibGdx. My main question is how I should structure my game? I’ve made a previous thread asking about Component-Entity Systems and that seems like a good option, but I want to explore my choices.

I want to be able to have a few XML or Json files with most of the game content in it, and I could read all the data into my game and have it create the required game objects.

So back to my main question, how should I be structuring this game? I would really appreciate any help or advice anyone can give me.

Thanks.