I started riding in 01/02 with a stock VMax 600ER. After that I bought a new 04 ViperER. I used to follow my buddy around on and off trail. I have only gotten my sleds stuck a couple times. I am very careful about where I go, but I could follow him anywhere. My wife got the VMax stuck off the trail in 4' of powder. I am thinking it wouldn't have mattered what you were riding in that 4' of snow, you were getting stuck if you stopped?
On the trails there is never a problem. They are very well maintained. If there is snow, there are groomers out. As mentioned, we haven't seen the snow we used to. This year though looks like it could be another good year. Sure hope so anyway.
I upgraded to a 136 1.25 lug track on the Viper this year in hopes of seeing a little more off trail. In the past I rode mostly on the trails. I did however my first year follow my buddy off trail. He was riding a stock VMax 500 with a 121 3/4 lug track. I was riding my VMax 600 with 121 3/4 lug track. We rode an old jeep trail for a few miles in snow that was well over a foot deep of fresh fallen snow. The whole time we rode we were leaving a foot deep path behind us. I was amazed at where these things would go in that kind of snow.
I am sure you will have fun!