DS was really easy at 6 mo. (last Oct). The weather was great too. He had fun people watching, was young enough to nap when he needed to, and it was a very smooth trip.
I took DS at 6 mo, 8 mo and 13 mo, and 6 mo was the easiest age. I was nursing, so we spent some time at Baby Care in each park. We also had two character meals - Crystal Palace and Garden Grill. Both places had infant seats for him (vs. high chairs) so it was easy for him. He loved the fuzzy characters at that age, and laughed and smiled with them. By 13 months he was afraid of them and screamed if they got too close.
On the darker rides he napped or nursed (like Pirates, Haunted Mansion). He loved Its a Small World, Winnie the Pooh, Buzz Lighyear, etc. We skipped the movies - we went into Mickey's Philharmagic, but realized that at his age, he did not get aything out of movies, plus it was just too loud for him.
We skipped Animal Kingdom, as he's really too young to enjoy much there. The best parks for him were Magic Kingdom and Epcot.
As I was nursing, feeding him was easy. He was just starting solids, so I'd have a few jars of fruit or cereal with me. We always had a change of clothes, and a baby sling was great because you end up carryign them so much of the time anyway.
We spent about 4 hrs per day at the park. Otherwise, we would hit the pool or just relax. Overall, it was a great trip.
I would just watch out for the heat. I've been there around Mothers Day when it's not too hot. We just got back from a trip over Memorial Day, and the last day there, at AK, DS started to overheat. We spent about an hour in Baby Care with him to cool him down in the AC before taking the bus back the the resort. It can just be really hot for the little ones. Also, try to get the baby used to wearing a hat - we did not do this with DS, so he will not tolerate a hat on his head at all. Makes it hard to shade his head.