We have a 2010 2720SD and bought a Calmark Cover that was custom made for our trailer. They have a 6 year warranty and are made of Sunbrella. They can be ordered from
www.calmarkcovers.com and their phone # is 800-838-7236. I will order another one when this one wears out. They don't show the Trailmanor on their website, but I used the HiLo template as a starter and then used my own measurements on the custom template to actually order it. I talked to the owner of the company, and he was very willing to help. We've used it since 2010 and it still looks very good. We live near Las Vegas, NV, so we don't get much snow or rain, so I can't comment on mildew issues only on sun and wind. Our cover is for a closed trailer.