If you were traveling alone or just traveling as a couple, it would probably be more costly to rent an RV. When you consider the rental price of the RV, plus the extra fuel for driving, plus the RV hookup fees, it would cost $300 or more per day. An inexpensive car rental plus budget motel rooms would likely be cheaper.
In your case, you are traveling with five people and would likely need two or three motel rooms every night. This makes the RV a very competitive choice. There are nice campgrounds within short distances from nearly every attraction. Many of these campgrounds offer swimming pools, laundromats, hot showers and other amenities. Nearly all Walmarts offer free overnight parking in their lots. They offer a free alternative to the campgrounds, as long as you frequent the campgrounds every few days to fill your water tanks and dump your waste.
On the plus side, the RV gives you a lot of flexibility, and a sense of adventure. They can be a lot of fun. On the negative, it is not much fun driving a cumbersome RV through city traffic or over a steep mountain pass.