Roof AC unit makes sense for a newer larger trailer where it can be ordered as an option. In our Trillium
4500, we have figured out we can use a portable AC on wheels with the old furnace
exhaust vent. Our portable AC on wheels has proven effective in cooling up to 300 square feet, so no problem there.
My thought has been we would rarely use AC, and haven't yet used it from MI in the summer to FL in the winter. As the seasonal temps get warmer, we always seek camping locations further north. Also, more and more of our camping is dry camping
, off grid where AC is not feasible.