Many rvs come with covers as an option or can be dealer installed. They are simple DIY projects. Added one to my New white hawk as soon as I got it home. Jayco doesn't offer it as an option. I would consider swapping out the stink fan in the bathroom vent with a fantastic fan vent. Great improvement over the little stink fan and does a wonderful job bring fresh air in to the TT via windows so you can cool your unit without using the AC when the sun goes down.
If you have a high capacity fan in the bathroom make sure you get the right type of cover, if you don't could damage motor over time span. Max air makes standard covers for vents with high capacity fan.