I'm looking for someone who's ridden through the Eastern part of the Mojave Desert/National Preserve. One of my trip planners has an option of going from Arizona into Needles, California, then North towards Las Vegas. There's a 46 mile road running pretty much North and South connecting Goffs and Nipton, Ca. called Lanfair Rd on the Southern end and Ivanpah Rd. on the Northern end. The National Park Service's website claims all of it is paved except the middle 15 miles, which they describe as graded dirt that all vehicles can travel- famous last words. I'm wondering how many LTs have they seen travel it w/o incident? Has anyone here done it, especially two-up on a heavy bike such as the LT?

Jeff can't answer that.
At the start of your Q I was about to say when I left the Grand Canyon on US 64 south into Williams picked up I-40 thru Kingman and Needles I was basically into the Mojave but that was the total extent as I continued west.
Similar predicament only for about a mile or so.
Tried to camp in Yellowstone but full. Ranger told me I could check out Eagle Creek campground just to the north and so I did. What starts out as paved soon turned into gravel and later into harden ground and loose gravel up pretty steep grades with 15 and 20 mile switchbacks. Well I needed the rest and the campsite so I did not let that stop me. One thing though if a turtle or snail were racing me to the spot they would have gotten it . Next morning I was freaked out coming down. Good thing I did not have to pee
ride safe

I’ve been on most of the paved roads in that area but am not familiar with Lanfair Rd. If you want to ride through Mojave suggest: East on I-40 to you get to Kelbacker Rd., then North on Kelso/Cima Rd., to Ivanpah RD to Nipton then North on I-15 to Vegas. I take these roads often way I go to Vegas as I can save 30 minutes vs. the Interstates. Last time was in May and parts of the roads were pretty rough but doable two-up. If you’re looking great scenery – the Mojave doesn’t do much for me. If time permits, go from Flagstaff to go through Sedona, Prescott to Quartzite, CA. Take I-10 East to Joshua Tree Nat Park. Scenery is a little better albeit different. Then head toward Amboy. From there you have several options including one through the Mojave. Keep in mind the low desert in the summer is really hot!