“The stretch from Salt Lake City to Austin, Nevada covers roughly 400 miles. Salt Lake City is your last resupply for food unless you take the 60 miles round trip detours down to McGill and Eureka, Nevada. As you leave Ibapah, UT you leave behind the last guarantee of water for roughly 200 miles.”
Also see the related YouTube video Jan posted.
[N.B. Uncertain whether this is still true. The route map shows water at Mile 1560, Rock Springs. See updated post here: “After this last ride I can now say that the longest distance between reliable water resupply is roughly 85 miles.”]