If the water is still open there look for were the rats are feeding. They will be tucked away platforms covered with left over roots, usually white or yellowish in color. They like over head cover for protection. Productive trails will be close or in the water.
Not a big fan of muskrat lures. Apples though work good for bait if you want to make your own feed pile or baited set. Make your set visible to the muskrat but bend the weed over to give cover over head.
Keep it simple.
Does the pond freeze in the winter? Could go after them under ice. That's my favorite way when I bring my boys along.
Good luck,
Wayne