I hope you're just driving through Death Valley Nat'l Park and not planning on staying long-term. It's still extremely hot there and have no idea what you'd do with your jet skis.
If passing through...and I don't know from which direction...Stovetop Wells would be the best place to stay right now due to other closings. Mesquite Spring is a pleasant campground, too. Stovetop is a huge gravel area with marked sites. However, since it's hot, there is also a row of sites with hookups, run by the concessionier. You really don't want to do any multiple days of boondocking in Death Valley at this time of year...much too hot.
Although the web site states Furnace Creek is closed...I'm wondering if that means all the camping areas at Furnace Creek are closed. You might want to call. There's a huge gravel parking lot with dry sites. There's a shaded area of campsites and there's a hookup area.