When calculating the price of towing your rig there's more than fuel savings you need to calculate. Buying and preparing your own food could save a small fortune not having to eat out all the time and this could drive the travel price back up. The price of lodging may tend to be higher than a campground or even "Walmarting" as well. If you fly, then you might need to add cost of rental car and eating out for pretty much every meal and possible higher lodging costs.
Then you need to also calculate that while you might spend less days on the road, you may spend more days at the destination at hotel prices in unfamiliar lodging and not campground prices in your own bed with your own conveniences.
Lots to consider and not as bad as one might think.