I have a cupboard full of products I've tried. There is only one way to keep your coach shiney.....wax, wax and wax again. There are no secret products.
Of all the ones I've tried, it seems the shine lasted the longest with NuFinish. I wax three to four times a year. I know most don't and many can't because of physical challenges, but that's the only way to keep them looking nice.
Here are a couple of things I do. I'm now one of those who is getting older and everything hurts. I use a rolling mechanic's chair (available cheap at Harbor Freight) to wax the lower half of my unit, which gets the most abuse. I roll down one side and wax what I can reach while sitting down (height wise). Once I'm done, I roll back and wipe off.
Almost every trip, I hit the front Diamond Shield/3M with either Pledge, 303 or a paste wax. This keeps it clean and easy to clean when we hit bug infested areas.