You're going to need to polish the surface to remove the wax and oxidation. It sounds like you might not have much in the way of exterior care tools, so I would recommend this
Random Orbital Polisher from Amazon as it's not too expensive and comes with pads.
The following polish is easy to use
Meguiar's Ultimate Polish
I would then recommend watching some YouTube videos on how to polish. One of the most important things is to do small 2' x 2' sections at a time as you don't want the polish to dry on the surface. When you're done polishing the coach you can then apply the wax and it should look great.
Good luck on your project.