IMO It's worth the flight to see it. Use as negotiation and see if the dealer will cover or adjust the price.
CPO gets you some degree of peace of mind but not total. If there is minor wear-and-tear, imperfections etc. it may still fly under "CPO". Also you may find things wrong that are covered but will still give you a major headache as you submit for repairs. What if there are squeaks and rattles? What if the car simply stinks?