I highly suggest going to the Disney website to see what they are offering. Most of the time their hotels are not any more expensive than staying off property and they are usually giving you the meal plan for free (which means you don't have to pay for any food!)! Staying on property also means you don't have to pay for parking (since you can take their transportation) which gives you savings of $14 a day!!!
Make sure that you book it soon and that as soon as you book, you make reservations at the restaurants you want to eat at. The good ones fill up quick, and you don't want to be stuck looking for a place last minute.
Utilize the Fast Pass system...it will save you SO much time if you Fast Pass the busy rides (Splash Mountain, Toy Story Mania, etc.).
If you get to the park first thing in the morning (and take advantage of Extra Magic Hours), you will get more done at the park. We have been known to be completely done with Animal Kingdom by noon because we go first thing in the morning before the park opens to everyone else.
Finally, buy all T-shirts you would want for your son ahead of time at a Disney Store. Disney does have some different ones, but they will cost you at least $20. If you go to the Disney Store (or Outlet) you can find them for $5 or less. If your son wants shirts (or other things like it), buy them at home and take them with you as a "surprise"...crazy savings!
We got to Disney every year, so if you have any other questions please feel free to PM me!!!