Go to deltaqueen.com and click on the "fares" button than select "specials". This will tell you what the Delta Steamboat Company specials are for the current time period. If you want more informatin simply call them up directly and ask. If satisified have your travel agent book you at the quoted special price.
Have cruised on Delta Queen twice, Mississippi Queen and American Queen once each.
Next cruises looking forward to are the St. Louis to Minnapelois run, Ohio River cruise and the Tennessee River cruise.
Check their website and/or give them a call and simply ask. What have you got to loose.