We did a split stay during the week of the 4th this past year...We went to AK on the AM of July 4th and it was empty for a good part of the day...We went to DHS in the PM for their display and it was not crowded at all...We went to MK on the 3rd for their display and the lines for the rides were long but not terrible (Fast Pass is key)...
We did the dessert party on July 3rd and it was sooooo worth it...We were relaxed and not crowded in at all....Main Street was mobbed....It was so bad that when we left that they did not let us out on Main Street...They actually had us go behind the scenes in the CM work areas behind MS...
SSR had a really big pool party the night of the 4th with a DJ, games and prizes....
It was very hot but we did the get out early in the day, go back to rest up in the afternoon and went back out in the PM...It did not rain all that much....
We had a great 11 days in Disney!!!!!