Welcome aboard, Michele! I hope you do book that Dream sailing that departs on Halloween! The cruises aboard the Disney Dream are always amazing, but in the past, the Halloween events and activities that have been offered have made for a really memorable trip!
Though the Halloween plans for this fall have not yet been announced, you can bet that they will be along the lines of what has been offered in the past. Read about last year's late October sailings in this
article on the Disney Parks Blog. I, too, will be setting sail in late October and hope that we'll be experiencing some spooky fun onboard! So, pack a costume and get ready for some Halloween fun, Michele!
Let me know if I can help with any other questions before you set sail this fall! I'm happy to help!