Just a follow up. Got my boy out to the slopes finally and I would say it was a fairly successful outing. I kept it very light hearted and let him set the pace. He would go down the hill about 3 or 4 times then tell me he was done. I would them unnstrap him and let him play in the snow. Then a little later he'd decided he wants to ride some more. I was amazed how well he was able to stay up. After a couple rides he kept demanding I let go of him and let him ride without my help. Very proud of the little booger.
After he was done we went into the lodge and he enjoyed some hot chocolate and snickerdoodles.
Thanks so much to everyone for the good advice.