I have done both! I do winterize, but I don't always close it up like I should, it's just according to what our last trip was like and when we came home.
I usually try to put everything up and in it's place before we leave our last campground. I will put all of our clothes in a storage bag to be brought into the house (we have camping clothes that stay in the RV during the season). All the food stuffs are put into bags to be carried back into the house and used during the winter, to be replaced in the spring. Our shampoo, soaps, toothpaste are also brought in to be used and replaced in spring. All the food/condiments in the fridge are brought in for use.
That being said, there have been a couple of years that we have left the last campground in the rain and lots of that stuff has just gone out the window. After about a month, I did get the condiments out of the fridge, but that was about it. When we did the first trip in the spring, it took me a couple of days to get everything clean and back into the correct position and ready to camp. (There are 4 of us, so it makes it a bit more stuff than a couple of people or, just one.)
Just start at one end and work your way to the other. It WILL take you more than one day or two. Throw out what you have no use for or that you didn't use last year. (That's my hardest part).