You might consider a telescoping ladder. I bought my 12.5' one last year for $54. It's now up to $81, but you might find one for less. It's easy to use, easy to store, and with a pool noodle (cut in half) you can cushion the ladder rails where they lay against the trailer roof to protect your TPO roofing and the rain gutter molding. Just be careful storing it, when you push the buttons to collapse it, it can pinch pretty hard if your fingers are in the way. Don't ask me how I know, just trust me on that bit of information......
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1