Nashoba usually has something in late April, Killington, Jay, and Sugarloaf may still be open, most places will still have their parks melting and left unattended.
Ive seen clips of people at Carinthia hitting shit after they closed. I say go for it, most places just leave features in the ground until everything melts anyway
Lupe is on the Carinthia team so I'm sure they had some help doing this from the mountain, but I'm sure if you asked and maybe mentioned you were making an edit or something they might let you do something like this in the Grommit park.