William- look at the map on this page of A Basin's website for a better idea of the locations. A basin map
Not on the map: Dillon (just east of exit 205, on the Summit CO side of the Eisenhower tunnel) and Loveland Ski area (at exit 206, just before the tunnel- actually, the tunnel runs UNDER the ski area). I agree that the most convenient lodging is at Keystone, but Silverthorne, Frisco, Dillon, Breck are all fairly close. There are a lot of deals out there now for April- you should be able to find something fairly cheap. The SUmmit Stage provides free public transportation, too, if you have the patience to wait for the bus.