Mammoth will have better conditions (most skiing over 9,000 feet, top is 11,000), with the upper mountain steeps possibly still with winter snow. But it's an extra 3 hours drive each vs. Tahoe. Within Tahoe Kirkwood, Mt. Rose and the upper tier at Heavenly are your best shot, all topping out about 10,000.
That said the spring corn can be delightful if weather cooperates. That means close to a week since last storm for the snow to consolidate, plus clear skies to freeze overnight and warm rapidly during the day. At Squaw and Alpine you can follow the sun exposures around the mountain on days like that, staying on ideal surfaces most of the time.
The key issue is that at base elevations of Squaw 6,200 and Alpine 7,000 it is less likely to freeze overnight than the other places I mentioned.