All of the full size SUV's are great buys for the very long term. You can put 250K miles on one and re-engine them for another 250K miles. If you trade every 2.5 years, they're going to be very expensive vehicles.
I ordered an Expedition once that got 19.75 mpg on its first tank of gas. But it didn't have the power to pull a travel trailer. With a full load of passengers and a large engine SUV pulling an RV, they're still going to get dismal fuel mileage.
Question is whether you're willing to put up with that fuel mileage for having so much room?