If you opt for March Mammoth is probably a good bet.
It's technically 'off season' for them even tho they will most likely still have a ton of snow even in an average year. You can probably get some pretty good rates for a ski in/ski out . Their base clientele are from LA and by march most of us forget about winter sports and move on to going to the beach.
Not to mention the Tioga Pass will be open and Yosemite is about an hour away. You may or may not need a car to get to Yosemite, but it's a must do if you're in the area. I know there are buses but from Mammoth to Yosemite might not start running until April/May.
Tioga opened in March? It wasn't open when I came through on May 1st, last year.....and that was a horrible snowpack year. Tioga won't be open in March.
Traveling the States and Taking Pictures