Jim, you said you were wanting information about the Butter Factory, (I assume that is distinct from the Creamery) but have you tried the County Archivist?
In their archives is bound to be a set of OSS's, and these will show at the least the ground plan of the Factory and the surrounding area. The best scale for you would be 1/500, the 1/2500 would be ok as would the 1/1250. The first two are older, the last more recent.
The cost is nor prohibitive, you would not need the whole sheet, just ask for what you need.
Regards,