To answer an earlier question, the message board service provides images of papers and cards found in the soldier's military service file. Information from those copies plus commentary from experts who have read thousands of service records offer you the best means to understand each soldier's experiences during the war. For instance, the gentleman mentioned who has access to Fort Delaware papers might be able to answer additional questions about prisoners-of-war being processed during the summer of 1862.
Feel free to reply with other questions.