I'm currently living in Mississippi but raised in Tennessee. My husband and I bought a 2008 Niagara (Model 4233) about five years ago. Super nice! However, we have neglected to clean the exterior and now it's a hot mess. Do you think it safe to use a pressure washer on the side body panels and roof? As I understand it, the side has the Krystal Kote finish; the roof is fiberglass. Photos attached. If you zoom in, you can really the see what I'm up against with what looks like mildew specks, etc. Thanks so much for your opinion(s)/thoughts. Happy Camping!