out of sledding in the mountains, and riding dirtbikes in the summer, id say snowbiking is the easiest of them all. no bumps, no ruts, no rocks, no hard surfaces, no tight areas (like for turns... you can take most turns as wide and easy as you want assuming you arent in the trees), no extreme traction issues where its hard to hold onto the bike. no arm pump on the snowbikes, no muscling around and fighting with a 500lb machine all day. crashing doesnt hurt as much,or at all sometimes. you can ride on 99% of the terrain as its snow covered.. cant do that in the forest or desert for the most part on the bikes due to fallen logs, rocks, mud, bushes, etc...
snowbike is very easy if youre just going out and ripping around. I almost found it too easy and dare I say "bored" at times because it was so easy!! so effortless. you can sit down all day and still go anywhere without hardly flexing a muscle in 2nd gear. I was able to go out 5-6 days in a row last winter whereas my sled buddies were BEAT after 2-3 days in a row. same thing with dirtbiking.. most people cant do 3 long days in a row.
getting stuck can be a little exhausting at times, especially if you dressed for the cold and it happens to be warm out. otherwise I think youd do fine and love it. once you get used to it, its a very easy sport id say. or maybe I just dont ride extreme enough. I went places the sledders didnt think possible... while sitting down, relaxed, putting in 2nd gear, no effort required. if they followed me they would be EXHAUSTED after about a quarter mile and not having fun. I got told a few times by guys on turboed 800s and brand new 850s that they "were jealous" and "two sickest lines I seen all day were on the snowbike".
the only downside to is it theyre damn expensive and not necessarily the most reliable toys out there (dirtbikes werent made for this... even if you spend $30,000 itll still be hard on the machine and wont last as long as a summer ridden dirtbike, or sled)