Our train tour was to many years ago to make a comparison but from the prices I've seen on their tours be prepared to spend lot of money.
The price of the cruise is usually affordable sine they'll make it up on tours unless you book them independently but even then they're still very expensive. It's something that most people do once in a lifetime & they take full advantage of it.
I forgot about the airfare since we don't normally use it. Being in Florida we mostly do the Caribbean these days & use bus transportation, which is also climbing with increased fuel costs.
I'm surprised that Princess hasn't reinstated their fuel surcharge.