Costs/types of RV storage shelter?

I have a 31' long, 18' wide and 10' tall leg (almost 13' at peak) Carolina Carport with the boxed eaves and paid about $2300 for it. Because of where we live, we had to have the one rated for higher snow load and higher wind speed. I figure this is a bargain to keep my roof clean and dry. I anticipate owning this house for at least 12 years. That equates to $192 a year for covered storage on my property.

I can keep my slides open year round, keep windows open to reduce humidity. I keep the area around the trailer dry so that we can load/unload without dragging in mud.