based only on the distance
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Well, all of the places you are talking about are amazing places, but Moab sticks out as the "one of these things is not like the other" when compared to Yosemite or the Coast.
Moab is certainly not like the other parts of Utah you are talking about, but it is quite a bit out of the way from the other places you are talking about. You'd be adding a decent amount of miles to get there.
Yosemite and the Coast are "right on the way" so to speak. While certainly both will take some extra time to stop and see, you have to head that general direction anyway to get from Vegas to SF to LA.