2005 gen 2 Prius help please !!

Thanks for any help.
I purchase a 2005 Prius with 185k miles that had a bad engine as described to me. With a motor from lkq that was certified 49k miles on it. I am curious if there is a way to diagnose if the gas engine is the only problem with it. I purchase the vehicle with the motor for 1k and didn’t think swapping it out would be too tedious but based upon what I’ve been reading it is not as easy of a job as I was expecting. A) I would like to know if it’s a decent buy, B) if there is a way to tell if any other major issues are wrong with it. I moved the car on and off the trailer car was very sluggish and knocking from failed engine. Also a bad odor came once the vehicle had been moved . Thanks for any advice and insight. New to the Prius but am hoping I can sort this out and make a profit toward getting a newer Prius for my pregnant girl friend. Thanks again.