u/Brave-Painting3180

I hope that someone can offer some insight on this issue. We live in a home where there is plaster and lathe underneath a poorly done drywall job and there is no attic access. My suspicion is that it may have been drywalled over, but how would I even begin to guess where the access would be placed, without taking down all of the drywall? The house is 1 and a half story and it's a century home. Any suggestions would be appreciated.