condensation

I have a double wide (1973)with a metal roof and condensation problems. after reading many comments, am I correct in the following repair. remove the damaged ceiling, insulate with R-38, installing a vapor barrier, adding a suspended ceiling (original ceiling is damaged and not able to support drywall) and providing ventalation at 1 sq ft per 150 sq ft of roof area. Do you think this will fix my condensation problem? or will I need to do something different? Thank you.