I suppose this is true about a lot of places but a nice thing about late season skiing is that road conditions aren't as bad and you can combine your ski trip with something else that's interesting. For example, if you go to Mammoth you could fly into LA or San Francisco (or even Reno) and then see stuff in those cities, or other stuff like Death Valley National Park in the desert, Redwoods near the Bay Area, the CA coast, etc. And Mammoth is really great in April. Plenty of snow falling now and forecast yet in March to set up a good spring season.
But all those other places are good too.