Hi Mike,
You have a 14' hauler and one roof vent into which you plan to place an AC. An additional roof vent, especially with a fan is really nice and I feel necessary to vent air and fumes from the trailer. I installed two roof vents with fans and both openings are framed for an AC ... if I ever add one.

Last trip out, we opened one vent and then opened the other and turned on its fan to draw the heat out of the trailer while opening the door and closing the screen door, the trailer cooled down quickly. The nights were cool enough that AC was not needed (I did not have it anyway), but opening both vents and the windows a little made sleeping great.
However, I do not want to tell another what to do as we all have our own ideas and plans. I almost died once due to a lack of ventilation in a camper and maybe I am now overcautious ... I also did not want to add the added weight and generator necessary for an AC, so I chose to go with 2 windows, a screen door, and 2 roof vents. A roof vent is nice and might be considered by some to be necessary ... especially if there are no other high vents in the trailer.
Keep after it and your trailer will make you proud! Add flics as you go, we want to follow your build!
