The weather forecast for Saturday calls for partly cloudy, which will be a gift. The Furnace Creek temp range is for a high of 81° and an overnight low of 38°. Yes, it does get cold on the desert! The relative humidity is going to be high about start time - 0700 - at 41% but that coincides with a 10% chance of rain [not likely according to our local weather guessers]. It will decline over the course of the day, as the temp hots up. Winds on the valley floor will be in the 6-8 mph range, mainly from the south. With that said, the course heads north, up Scotty's Castle Rd to the Castle, and thence onward up Grapevine Canyon to the Nevada/CA state line and the "slog" across the Bonnie Claire Flat to Scotty's Junction at Hwy 95. Then it's back across the Flat to the Castle, and the somewhat direct return home. Scotty's Castle is approx. 3300' above sea level so the "climb" from the start point is ± 3500'. Bonnie Claire Flat, 5 miles further up the canyon above the castle is at 4000'. The temps, once you're that far along, will bare no resemblance to the Furnace Creek temps; count on 5-10° cooler, depending on what the winds are doing up on the Flat [it's true high desert country - wide open and subject to slight weather changes]. There is no real way to forecast wind conditions up on the Flat as it is a remote as it can get. I have experienced snow showers [unlikely this year], strong winds [always a possibility], plus the unrelenting "slog" for the 42 mile round trip from/to the state line. It is exposed ground, nearly flat with only a few small rollers. Tedious is how I describe it. There have been instances where the return leg back towards the castle have been "improved" by a tail wind; not frequently, but it has happened. Once back at the state line it's all down hill, more or less. There's the drop to the Castle for a CP, and then the leg out to Ubehebe Crater, another mandatory CP [all new road completed this past spring!] and then the e-ticket ride back to Mud Canyon - ± 33 miles - which is followed by the climb up to Hell's Gate. This is the one true challenge - 7 miles at between 6-8%. Once at the Gate, it's a 10 mile descent on the Beatty Cut-Off to CA190, and then an 11 mile run back to s/f. The key to any "desert" ride is to stay hydrated, and like any other distance ride, fueled. Make sure you stop at each CP and keep your bottles full; take your Endurolytes and grab food to take with you and eat on the bike [no trash disposal on the desert please!]. I find that this, the north course, is much more interesting than the south course to Shoshone. But then, I ride that section pretty much weekly.

In any event, enjoy the ride! Death Valley is something to behold.
YMMV
-dg