LT1050, oil leaking onto mower deck

A friend called with a LT1050 and said he noticed oil on his mower deck, oil level was low and when he started engine and engaged the deck, smoke came from between the engine area and deck. He shut it down right away. He called me to take a look at it so I'm heading down soon. So, I'm guessing that perhaps the bottom crank seal has leaked the oil and leaked onto the PTO and caused the smoke.
Do you guys think this assumption is correct or it there something else that could be leaking? So if it is the bottom seal, does the PTO and trans pulley get pulled and seal pulled out and just replaced? And is it much to cleaning the oil off of the PTO. Any other ideas or tips appreciated. Thanks