Honestly given the March torch and complete lack of snow that month I'm shocked we're still skiing on anything outside of the Superstar pod this weekend. It gets cold tonight and the next couple nights along with a rain/snow event which should be a net gain. Even Sunday looks like it will be another mostly snow event. Very impressive turnaround. All things considered April has been very dry and just a handful of days in the 60s and 70s. Terrain-wise we're skiing on what we normally would be doing in a good year. I remember 2 or 3 springs ago they were just down to the Superstar quad and a trail off of Snowdon at this time. The big hill on Route 100 between the Skyeship and the Killington access road had large spots which were washed out.
If Sunday can stay mostly snow I think they could run the K1 in May, which is quite rare.
Online lift ticket sales are available weekends til May 31st. That's clearly an error as that is not happening this year save for Yellowstone erupting and we get another ice age. But as of a couple weeks ago they were only selling through the first weekend in May, so maybe it's a good sign?
Where are you seeing that Sunday will be mostly snow? I'm seeing rain well into Canada with that one. NWS point forecast for 3400' elevation at Killington shows highs of 41 on Sunday and only dropping to 32 Sunday night.