I am glad you posted this. We too are taking our 14 month old to WDW (4/22-4/30). While in the past I've planned every day out methodically, for this trip the only thing I planned is a character breakfast every day, which is totally flexible too!! My husband & I agree that we just go with the flow & let our son set the pace & plan to go back to the room each afternoon & try to nap. While I haven't done the trip yet to give you 1st hand information this is what I've done so far to try to prepare:
We just bought a new stroller for the occassion. We did just what tjmw2727 said to do: went to BRU and tried them all. We chose the Graco Metro Lite: easy to close, light, reclines almost flat, has a sun shade, cup holders for us & son. But, when reclined it's hard to get to storage basket - we can live with that. I also like tjmw2727's suggestion to get the clip on fan - I will have to go get one.
For food - our son is still partially on formula as well as whole milk, so I bought a can of powered to take w/us. As for food I am packing his snacks (Gerber crackers & the like) and fruit cups, but he is mostly on table food at this point. We are getting a town car so we will stop at the grocery store because although I am packing some diapers if I pack as many as I think I'll need (60 or so) I'll have no room in the suitcases for our clothes!
I have packed tons of sunscreen specifically for my son, as well as a sun screen chap stick for babies. Also in my bag of tricks are bandaids, bacitracin, (my son walks but trips every now & then & I have visions of him, in shorts, tripping on the pavement...his 1st skinned knee!), teething gel & tylenol (teeth are coming in rapidly now), our own sheets for the pack N play, a few toys from home (I don't know how he's going to handle a strange room for a week, so I thought some items from home might make him more comfortable).
We too are very excited about taking him on his 1st trip to Disney!!! Just 9 more days to go!
I hope you have a wonderful trip!