Forgive me if this has been asked one thousand times before, but I haven't been successful in finding the correct answer anywhere.

Ever since Steam changed the Launch Options function, my Lord of the Rings mod to Rome Alexander no longer works, since it relied on that function to launch. I haven't yet heard of any alternative method to launch it. Even the pages that discuss this mod in particular only mention the Launch Options as the launching method.

What am I missing? How am I supposed to get a mod to work in the new Steam system? I'm sure the solution is supposed to be simple, but I have no clue.