I think the 4th is a good date. Although the Halloween time last year was busier than I have seen it in the past it was a fun time to go, especially with the Space Mountain/Ghost Galaxy. The weather is lovely with little rain if any and the it is all decked out for Halloween. I think the longest wait times we had were maybe 30-40 minutes for the E ticket rides, but we just used our fast pass for those rides. They do a trick or treat party at the DCA park, extra money of course, but I don't think it will be as busy as the end of the month will be. IMO Gays days is the 1st-3rd of Oct. and that should be busy but I think it will have slowed by the 4th.