We just bought a mobile home and had to paint the entire house and we had vinyl sheetrock. I would not peel off the wall paper if there is any. You can paint right over it. The best way is to use primer white paint on it first and then you can paint it any color you want.
It is best to use a drywall primer, this will allow good level flow over any sheetrock in a mobile home. Paint with latex paint after primer dries (2-4 hours)
Most important thing is going to be a good primer so the paint sticks to the sheetrock instead of peeling off. I would recommend a good primer like Kilz, which will be nice and thick.
