Arlene,
We have been to Orlando and Tampa (my sister lives there) in November many times and never have had any weather problems. As for the rides at the Magic Kingdom, there are quite a few that he can go on and there are now area's in the park for younger ones. He I am sure would love; It’s a Small World, Winnie the Pooh, the Dumbo ride, Cinderella’s Carousel, Country Bear Jamboree, Fantasyland Play Area, the Jungle Cruise, the Peter Pan ride, Mickey’s Toon Town has quite a few rides and you can meet Mickey and other Characters there and have photos taken. One of you can do the Tomorrowland Speedway with him and in-between if you two want to go on something (that he can’t) you can always do the baby pass. This would allow one of you to get on the attraction and the other to wait at the exit and when you get off the ride the other hands the boys off and he then gets to ride and you don’t to wait in line again. Height restrictions on rides are sometimes for the whole ride and other times it would just mean that he could not ride alone. I made a little chart for my boss when she took her 3 year old last year and I would be happy to send it to you if you would like it.
If you are going after November 10th, you could also attend Mickey's Very Merry Christmas Party, which is very cute and has all kids of things for kids. If you need any more information on Disney please let me know I would be happy to help.
J.