Hi Sean!!
How wonderful to be going for 3 weeks - that's plenty of time to take in loads of things but also to relax - which is really important when you have a little one with you.
My DS had just turned 3 when we took him last year and unfortunately he stayed awake the entire flight (both ways) so I am glad I took plenty to amuse him. You might find however that your DS sleeps. When my DS was 2 he fell asleep on flights (we never did go as far as the US however). The constant white noise and movement of the plane seems to send toddlers to sleep quite easily.
I remember when our DS was that age he liked lift the flap books, "Stuff" from ELC, fat crayons to scribble with, jigsaw puzzles, finger puppets (I used to get story books with finger puppets which he loved). Also, his favourite book I remember was a Dorling Kindersley book which was just full of photos of everyday objects and he could sit for ages pouring over the pictures with me.
He also loved tractors in particular. You can also take him for walks up and down the aisles and perhaps buy him one of the inflight toy planes (they are only a couple of inches long). He'll probably get a bag with some kiddy stuff in it - crayons, jigsaw puzzle, colouring pad.
One tip - if you want the child's meal - phone up the airline and book it especially. Many airlines don't automatically hand out a child's meal and may well give you nothing at all!
I haven't stayed in Silver Lakes but it is very close to where we stayed last year. It is very near to the Disney maingate and to Splendid China. There are loads of restaurants nearby and there is a useful shopping area (right beside Splendid China) where you will find a supermarket and a pharmacy amongst other shops.
Yes the water parks are warm enough in Novemember. They heat them year round and the water is normally much warmer than your average villa pool. I think too that with all the "scenery" around, those parks seem to hold in the heat! You will get more rain than in the summer months so a good tip is to buy a rain poncho, and take a raincover for the buggy (I would suggest that you take your own buggy with you - don't hire them). Ponchos are sold at the Disney parks but you can get cheaper ones at most supermarkets.
I would also advise you take your own car seat - you may be taking it for in the plane anway - but if not, it's worth bagging and putting in the hold (you don't get charged for this) as the seats there are expensive to hire and are often little more than a plastic grubby shell.
Check out
http://www.ticketmania.com
for info about all the different park's tickets. Many DiSers have used this company to buy tickets as they ship postage free. They are very reliable and the prices are very good.
I think you will be able to work out from all their info which tickets will suit you.
Have fun!!
Jackie