One of my friends smokes cigs on and off the mountain. A couple others I know do not smoke on the mountain, but I think it's only because they can barely ride and they would try to manage both, if they could.
I would never do park high or drunk. Maybe go on the cruise at the end of the day, that could be pretty relaxing if you ripped a bowl and weren't doing anything technical. But doing anything that requires precise timing and coordination is not a good idea inebriated. I know people undoubtedly do it, but for me personally, it's just not a good idea. It would feel like 5 or 6 seconds in between kinks, and that's a recipe for tacoing or even worse.