There is always plenty of snow still at widdow maker and all of the usual back country spots, but you have to hike. If you go early you can use skins or snowshoes, but the later it gets, the less snow, and the bigger pain in the ass it is.
No body is ever around, people hike on Alpental all the time post season. They can't do anything anyway, they don't own the mountain, the forrest service does, what are they gonna do anyway, pull your pass?
Ok i'll tell you my secret post season kicker building spot. If you go to alpental and hike up to st.Bernard...go to where the cat track was made and look up to the left. You can make a real nice gap jump there, the snow is always soft it just might take a couple hours of digging. I've done it a couple times and its nice