Thank you to everyone for their input and the advice to use a white microfibre cloth so the colour wouldn't bleed from a coloured cloth onto my trailer. I couldn't find a white one so I soaked my neon orange one in bleach and never had a problem.
With all the rain in the PNW I finally got the Zep on, and how does it look? Amazing!! I think I did 4-5 coats and I couldn't be happier with the results.
My trailer originally looked like it was a huge piece of chalk and now it shines so bright. My trailer was so chalky that if this didn't work I wasn't going to be upset because as far as I was concerned nothing could look worse than what I was starting with.
I took an oil based paint
pen and went over our rock guard / window to enhance the original decal and I think the trailer looks like it had a facelift, or Botox, took years off!