obivously...
the closet thing that is going to get you ready for a fight is actual simulating the FIGHT ITSELF and I think you acknowledged that so #1... if you can do what you can do to simulate a fight because...
You dont get ready to fight brock lesnar by chopping down a tree (but it could help) but even still...
the best way to simulate a fight is do something that combines heavy weights & cardio at the same time like a tire flip workout, sledgehammer workout, circuit training etc.
see the video below for an example of a sledgehammer workout that would help you get ready for a fight...