If you want Tahoe legal, hustle over and buy this direct injection 2-stroke ski:
http://x-h2o.com/index.php?threads/...al-stand-up-jetski-jet-ski-16000-reno.199564/
You can likely also buy the Kawasaki SX-R 1500 4-stroke and the soon to be released Yamaha 4-stroke.
But I fear that it will be like going from your home built trick airplane to a Boeing 737. Yes, you can probably barrel roll them, but they are likely not really made for it.
And yes, it is fun at your or our age. Why? Because the only thing that keeps men alive after a certain age is good physical conditioning. And I have never been good at going to the gym. I was always in shape because of sport. But my wife and I stopped white water kayaking around ~2010, so my upper body has been falling apart. Jet skiing 3-4 days a week is slowly bringing it back. Make yourself do it. Pretend you are going to the gym. (That is what my wife calls water skiing with wind chop or tide rolls.)
There is nothing better than a hot day ~100F+ and being wet. (Although, a powder day at Kirkwood is just as good for Winter time fun.) Be gentle with your body, but get out and ski. Both physical conditioning and the satisfaction of achievement will come the more you ski. You will not ski alone for long.
Unless you are riding Tahoe. I never see anyone riding Tahoe. And once the glass disappears in the early morning, I wouldn't want to ride Tahoe anyway. (It was so windy on the Sacramento River yesterday after work that it wasn't fun. But I needed "to go to the gym," so my body thanks me for it today.) The other sport you could add to the mix is windsurfing or kite boarding at Washoe Lake.
Edit: And oh yeah, I forgot about the ice cream headaches that the cold water in Lake Tahoe give you even on the hottest days. Personally, I have no interest in jet skiing on Lake Tahoe. . .