Thank you for all your responses.
We ended up staying on the west side at Dr Babler Memorial State Park. It was about 30 miles from downtown but an easy drive down 64. It was a very nice campground with plenty of wildlife.
Very simple as it just had electrical hookup at site but with 75 feet of hose you could hook up to water or refill your tank. Plenty of shade at our site.
I strongly recommend the concert and fireworks show under the arch. It was quite the scene (hundreds of thousands of people) and the atmosphere was really cool.