I'm sorry but this is not how Ready works. A ready action can be a single action or move, not both, and it must be declared during combat. In your example the Fighter can Ready an action to move 30' to the door
or he can be at the door with sword raised ready to swing when it opens.. but he can't do both.
- If you are readying a spell, you cast the spell and hold the magic (which arguably is visible to those observing you).
- If you ready a ranged weapon, you have the spear raised, the arrow knocked, the sling spinning
- If you ready a melee weapon the weapon is in your hand and ready to strike.
- If you ready a move, you are in a stance that will make it easy to sprint in a particular direction.