Where you planning on turning east at Lone Pine and heading into the heat of Death Valley? There is a reason it is called that, 130 was a record heat in the summer, I would avoid it. Yes it is longer to drive all the way south on highway 395 to highway 58, then east to I40 and take that directly to Williams AZ, just south of Grand Canyon.
At Grand Canyon, the only nearby full hookup sites will be the trailer village just outside the canyon. At around 6,500' elevation, it should not be "really" hot, but expect the 70's at night. Check weather.com within 10 days for exact temps to expect. In May, you can check "Monthly Weather" and then click "Next month" to get the averages of June. I would rather stay without hookups inside the park, or dry camp in the forest south of the National Park (no dry camping within the park is allowed, but feel free in the Forest. Problems is the boundary is not well marked.
Within the park, there are several good campgrounds, with great views within a few hundred yards of the RV parking area. Take a bike, as walking around at the higher elevations might be difficult for most that live near sea level, you probably are used to the higher elevations and it can take your breath away!
Have a great trip.
One of my favorite stops while taking interstate 40 is to spend the last night at Laughlin NV. Taking the route south of town to I40 is not much longer than staying on I 40. The road from Kingman to Laughlin is STEEP so select a lower gear when going down the 7% grade, I think it is about 5 miles long. It was only about a 6 hour drive from my home in Orange County CA. Riverside had great buffett for a reasonable cost, and would send out a van to pick up the passengers if you requested one. The full hookup campground has 30 and 50 amp plugs at each site, has great showers, and you will need the A/C that time of year. Elevation is around 950'.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
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