I was just on US 95 from Las Vegas to Beatty. There is a Buddhist temple just off the highway in Cactus Springs, they welcome guests but they'd probably like a donation. It is far from ideal, light pollution from the two close billboards and highway noise. There are roads going off off both sides of 95 after you get past Cactus Springs. North of Amargosa Valley the space between Nellis AFB and US 95 gets a little bigger, so more accessible.
On my return, I used the road through Shoshone and Pahrump to Las Vegas and thought the road was much nicer with more camping possibilities, so you might consider that route.
Very little in the way of supplies in Beatty, get what you need in Las Vegas, and you definitely want to fill up in Nevada.