Are you camping? That would be my advise: To Camp by either tent, pop-up or small trailer. I can think of nothing worse for kids than having to stay in some sterile chain motel off the strip somewhere, night after night no matter how many great places you visit during the day. It just defeats the whole purpose. Plus it costs a bundle of money.
Think about it. If someone were to give you $1,000 toward your vacation but you had to come home as soon as it was spent, you could probably stretch it out to almost a month if you mostly camped and cooked your own food. This includes paying for admission to some of the attractions for the day trips you are planning.
On the other hand: Stay at a motel and eat out everynight, and you'll be back home in a week. Because if you stay at a motel, you have to eat out as well most likely.
On vacation, motels are OK once a week or so, to clean up and decompress. But never the whole trip.