I did a bit of research. Taking the Auto Train could actually be cheaper than flying and renting a car. I did a quick search for plane tickets for the five of us, and the cheapest flight I found was $472 one way on Air Trans, coach. Add an average of $571 for car rental. We'll be there for ten days, and I searched on a full size SUV, to be comparable to our four-door truck we would have normally. So that gives you a rough total of $1,043.
Five coach seats and the over-size vehicle fee on the Auto Train is about $660.
Our price will be more on the Auto Train, because we are opting for private rooms rather than coach seats. That's not even an option on a plane. Sure, you can go for first class, but you're still stuck sleeping in your seats in a room full of other people. I think our total for five train tickets, two rooms and the over-size vehicle was right around $1,000. That is before we apply the 20% discount off the regular fare by using the Orlando Magic Card. That will knock the price down by about $80 (discount doesn't apply to the bedroom or vehicle charge, just the base ticket).
I think that just the experience of traveling by train will be worth the cost, though. It's most likely something we won't do again, but will really enjoy and remember. I'm hoping, anyway!!