Based on your listed needs, I would consider a Ski-Doo with an Ace 900 or Ace 600 4stroke. They should last a long time compared to a 2stroke motor. Truth is, any snowmobile will do what you ask.  They will only go as fast as your right thumb lets it.

Grand touring like this one would be like riding a Cadillac.
https://www.ski-doo.com/us/en/models/trail/grand-touring.html