I recently rode the Western Express (Cedar City to San Francisco).
I wasn't carrying a cell phone so can't advise about cell service.
The shoulders on US50 are variable and many sections have rumble strips, although there are some sections that don't. The worst sections are the sections from the Lahontan Reservoir to Fallon (approx 20 miles) and then from Fallon to Sand Mountain (approx 20 miles). The shoulders on both these sections are all but unridable, and there was a large volume of heavy traffic along this section (between Sand Mountain and Fallon) when I rode it. Try to avoid the Fallon to Sand Mountain section on week-ends or public holidays.
Elsewhere, it is possible to ride to the inside of the rumble strips, along those sections which do have them. You will find a lovely, long flat section of newly surfaced road on the way into Eureka.
The grades of the climbs are not overly difficult, however, the wind is the greater factor.
In the main, I found the traffic along US50 to be very courteous and gave me as much room as possible.
I see that you have made reservations for your accommodation, which is a good idea. Motel accommodation can be a bit tricky otherwise.
It is magnificent country to ride through. Very challenging but equally very rewarding.
Hope this helps. Have a great ride.