I also use a snow brush like the one that I have for my truck. It is extendable and looks something like this one:
I remove the snow about 4 or 5 times a year and have not damaged the roof material, seals or any other items.
HAPPY CAMPING!! :D
Daryl and Sandy
2013 Eagle 314BDS
2012 Ford F150 Platinum, 4 x 4 Crew Cab with Ecoboost