We used a cover called PolyPro 3 from Classic Accessories, worked great, it made it through three Iowa winters and was still in decent shape. We recently traded in our 1207 and left the cover with it. I am sure it will make it a couple more years at least. Just watch any sharp edges/corners, they will cut the cover. We actually just bought a similar cover for our X17Z.
2013 Starcraft Travel Star 229TB
2011 Jayco X17Z(traded in)
2010 Jayco Jay Series 1207(traded for the 17Z)
2011 Chevrolet Silverado 2500HD Z71 CC 6.0L/3.73
Reese "Pro Series" 800lb Trunnion WDH w/sway control