I looked at the wind forecast at a bunch of locations along the published route and the highest forecasts I saw were 20-25MPH winds with 39-42mph gusts; mostly along SR-62 through Morongo and Yucca Valleys and the N side of Joshua Tree NP. The forecasts were 8-10mph lower down on I-10 and 60. Peak winds are from 11am-1pm and the winds will be out of the North.
The info was from the Dark Sky app on my iPhone and the NOAA/NWS website; both of which have been pretty accurate when I’ve used them.
And I agree with John: Riding an RT through crosswinds like that doesn’t appeal to me. I’ve done it before and only thought it was fun for a mile or 2.