I want to add a 2nd air conditioner to a 2009 Sundance 287RL XLT. I want to know if anybody has a picture,diagram or a blue print of the roof truss locations. I dropped the front air vent down and it is boxed with aluminum square tubing. I don't see any support for it. It looks to be only screwed in from the top. I know the brochure shows it will support a 3700# truck but can I just add a 100# air conditioner to it with out adding reinforment to the air vent opening?