Tug-N-Hug,
Take a look in the pictures of our winter cover on "Tuglet" (you can search "Tuglet" in owners pictures)
We are located on New Hampshire's Lake Winnipesaukee and winter over in Massachusetts.
Hence, Snow load was a concern in the purchase. It has pockets for 2x4's, a zippered door and is custom designed for the R21.
I am very pleased with it. I believe we purchased it in 2012 and is still holding up extremely well. Many years still left.
We chose "Fisher Canvas" in New Jersey. They made a pattern and will still have it.
They have a great web site explaining their covers. I do not remember the cost but 1200 (in 2012) comes to mind. Great people to do business with.
I understand King Canvas also has a winter cover and they are makers of the Factory canvas pieces (we just got a new Surry cover for Tuglet from them).
I agree with "CN" a cover, for us, is money well spent.
Dick