Might head to Cannonsburg Saturday with my son (4yrs old) and get him either skiing or riding. He can make it down a hill by our house with a cheap plastic target board, so it's worth a shot.
I'll tell you what, you can be surprised by what they can do. Our daughter was 4 when we first took her to Caberfae last year and she didn't get it right away but she had fun. That was the most important part.
Last weekend we paid the 39 bucks (which included rentals and everything) for the 2 1/2 hour ski school. We left her alone for it and came back after a couple of hours and she was able to go up the tow rope and come down the bunny slope to a complete stop without any help whatsoever. And she didn't want to leave when it was time to go. Money well spent.