Or, if the tarp on the sewer hose doesn't work for you, there's a dump station at the entrance to the parking lot for the showers/laundry.
Camping aside, it's one of those places you have to do at least once, and stay for at least 3 days, to really see it. There's also a CG out to the east called Desert View that's first come, first served. Another option?
Mike. Comments are anecdotal or personal opinions, and worth what you paid for them.
2018 (2017 Sprinter Cab Chassis) Navion24V + 2016 Wrangler JKU (sold @ ????)
2016 Sunstar 26HE, V10, 3V, 6 Speed (sold @ 4600 miles)
2002 Roadtrek C190P (sold @ 315,000kms)