You're making good progress. Congratulations.
Originally only two BonAir Oxygen trailers to come to NS, ours with the A/C and another with the ceiling vent. I have attached a photo which shows its position. The original owners only had the trailer for one season. We have owned and enjoyed this trailer since May 2004.
We are fortunate to have the manuals for everything on our trailer. The A/C is a Due-Therm 579 Series BRISK AIR Roof Top Air Conditioner (pre-wired for optional heat package.) The specifications in the Installation & Operating Instructions state the installed
weight as 95 pounds.
The A/C has never given us any challenges or concerns, although snow on the roof along with the A/C might be a concern, if we didn't store it inside each winter.
If I may help further, please ask.