We skied on the last day of Whistler this year which was April 19th I think and the skiing was fantastic. Snow falling heavily in the morning and fresh powder on the Friday but that apparently was unusual. Winds were a little high and it was icy under the powder. By afternoon the winds had exposed the ice on the lower sections. In the morning it was -19C at the peak. Blackcomb is opened till later in the year but we didn't ski it this time. The conditions actually didn't look as good.
As to what else is to do, well we were exhausted from skiing and walking so we welcomed a lovely long dinner at nights and time on the patio people watching. Plus we had a nice double jacuzzi so............