Very tempting. BUT, my experience last summer in Texas 100 degree heat with an 8000 BTU (2 hose) portable leads me to believe it is too small for a 13 footer. Best performance I could obtain with my 8000 BTU was a 20 degree differential during the day and about 25 at night.
If it was available for around the same price at 5 or 5500 BTU, I would give it a try.
Not having an A/C is the only thing I don't like about my trailer. And it is a major dislike after summer temperatures this year discouraged me from even going camping.
2005 Trillium Outback w/ 30" tongue extension
1989 Award 730, 30'
2003 PT Cruiser
1998 K2500 Chevy Silverado 6.5 Turbo Diesel, 4X4, ext cab, short bed