I have used ADCO Aqua-shed covers in the past with good results. If you cover the sharp objects on the roof with foam (something like pipe insulation) and secure them properly you will get a min. of four seasons and no paint damage. With the New England snow/ice and all the stuff that falls off the trees (leaves in the fall and pollen in the spring) I still believe it is worth the effort. The only down side is you will need to wait for the snow to melt before removing it so if you are planning a mid-winter trip down south I would hold off. Good luck.
Lou
05 Travel Supreme Envoy