Yes, the CPUSA had such plans: I will answer your three questions specifically, but first a word on sources.

Most historians of the CPUSA view William Z. Foster's Toward Soviet America as a legitimate source on details of the prospective rule of a CPUSA government, me included amongst them. It should be noted however, that certain other historians, most notably Harvey Klehr, view this book as no more than propaganda. Browder's writings can also be consulted (this answer, however, will mostly concentrate on Foster's conception of a United Soviet States of America (USSA))

Firstly "How would it divide the country?". The country would be divided into Soviets (councils) based on the Russian model, which, in Foster's words, would be "combined by direct representation into county, state, and national Soviets. The national Soviet government, with its capital in Chicago (….)" would be the central executive power.

Secondly, "How would it raise an army?". It is highly probable that, as outlined by Foster, the USSA would raise a Red Army by a combination of forcible conscription and incentives.

Lastly, "How would it deal with its enemies?". In conjunction with the aforementioned Red Army, the USSA would most likely organize a security service based upon Lenin's Cheka.

If you have any other, more specific questions, feel free to ask. As secondary sources I would recommend Ottanelli's "The Communist Party of the United States",Klehr's "the Heyday of American Communism" and Isserman's "Which Side Were You On: The American Communist Party During the Second World War".