I have a SV264... same floor plan as what you're ordering. In 2012, I spent 8 weeks in July and August in North-Central Texas, working my new job, while my home sold in Amarillo. Depending on where you are, you may need 2 A/Cs... I sure did! The 50-amp cords are heavier but this is one of those things I'll never be without when I trade up, next year. It's my understanding that the Atwood A/Cs are quieter than the Dometic units. Unfortunately, I believe Surveyor uses only Dometic units. If your location is marginal, you may opt for the wiring upgrade, and a 15,000 BTU upgrade for the single unit. If you need the second unit, it can be added easily because it's wired, already.
J & D in Lovely Weatherford, TX
2016 Jayco White Hawk 28DSBH TT
2014 Ram 2500 Crew Cab 4X4 6.7L Cummins