I bet your truck has at least 8" of ground clearance and should be able to backup into the space over the snow. All you would need to shovel is the area around the rear steps of the camper.
I spent last week in Yellowstone and was shoveling my friend's driveway and back deck after each big snowfall and it was not a chore. Drier snow in Montana than I am used to so it was a bit of a treat in some ways. Having only 20 vehicles in total along the road going into Lamar valley each day was so much better than being there in the non-winter months.