My late wife was a massive Disney fan, and when she was diagnosed with the dreaded 'C', we went to Disneyland in Florida. We stayed in the Pop Century hotel, which was fantastic. They have on-site arcades, shops and a food-court that is open from early morning until late at night. We bought the whole package through Virgin, and I think we paid about £3300, which included flights, 14 nights in the Disney hotel, unlimited access tickets to the parks (there are two groups of parks, the Disney theme parks, and the SeaWorld/Busch Gardens/Universal parks, so you need tickets for each group), and two weeks in a Chrysler Sebring convertible. That was about 4 - 5 years ago, so prices will have changed since then. I can't comment on the bus service, other than to say there are a lot of the I-Ride buses, and they seem pretty frequent.
We were both in our mid 40s when we went, and it was absolutely amazing. I don't think I have ever spent two weeks, with such amazing people in my life. My wife had major facial surgery as part of her treatment, and over here, she was always getting comments and being stared at, but over there, she was just like everyone else. Nobody stared, nobody cared, although she did get comical comments from the kids round the Pirates of the Caribbean ride, because she had to wear an eye patch as a result of the surgery. But kids are so innocent, so she just laughed with them.
She came back with an autograph book filled with signatures from all the characters, and I have photos of her with them all. We did all the kid's rides, because the animatronics in them are amazing. And trust me, you will see just as many adults on them, as there are kids. The parks are unlike anything you will have seen in this country, and the Kennedy Space Centre is excellent. We ended up going three times in four years, before she finally became too ill, then sadly passed away three years ago. But the memories I have of those holidays, are worth every penny we spent.
I would recommend a holiday there to anyone, without a moment's hesitation.
Edit: Oh, and we went late September/Early October all three times, so you get to see all the Halloween themed stuff in the parks. It's a big thing over there, it was really good.