Someone posted above (perhaps Alex?) that the 140 was blocked by a rockslide, and there was some kind of rigged-river crossing to avoid that section. I have no idea if that's accurate, or what vintage the alleged rockslide is.
In looking plainly at a map, however, Alex's "recommendation" of a shorter route via the 49 vs. the 99 looks to be half-dozen of one as far as distance. But in fact, the 49 is a smaller road, way more curvy, and goes through even less civilization than Turlock and Merced. So that's the one I'll pick!!
Um, there's not even ANY towns along that road, so I hope there are at least gas stations every coupla hundred miles.