A tourism study shows traveling by RV may be the most economical. To fly with the kids could be well over a thousands dollars, even if you book in advance. Plus add on another thousand dollars with hotel reservations, car rental and eating out.
Most people think they can save money by driving their own personal car.
Now if you can't see yourself owning an RV or you can't fit one in your garage, then consider renting one. A rental RV could still save you money because you're cooking your own food and sleeping either in the RV or camping out.