Just make sure you are relaxed. Your DS will pick up on it if you are felling stressed. Allow yourself plenty of time to get places so you won't be too stressed.
We (My DM, DNiece20, and myself) took my DD to WDW for the first time when she was 2 and 9 months. It was her first time flying and longest trip away from home (before that we had driven down to San Diego for a few days a few times) I was worried she would be scared flying, etc. but she was a real trooper! Since there were 4 of us flying we separated into 2 groups of 2. I figured there was no way a single traveler would seat next to a 2 y/o. Boy, was I wrong. On all legs of our flights someone sat next to my DD. Little did they know she was a talker (even then!). She bent their ears for the entire flight except for the brief time sleeping. Luckily for me, she is now a seasoned flyer and has never had a tantrum onboard (or even at WDW)
As far as sleeping went, we took our own stroller (A blessing in the airports to carry things to the plane) and she took most of her naps in it, at the parks. If she fell asleep while leaving the park I was able to keep her in it all the way to the car and sometimes managed to get her in her car seat before she woke. I didn't try to schedule nap times since I knew coming from CA that the time change would mess things up anyway. There was one a.m. where she fell asleep on the first ride of the day (KS at AK) I think it was about 9 a.m. The change in her sleep schedule got to her.
On that trip we also had to deal with her not wanting to use the automatic toilets.

If your DS isn't potty trained yet at least you won't have to worry about that!
Bring plenty of things to amuse him on the drive or flight. Pack away some surprises to give to him (wrapped) for those times when you want to distract him. Of course you'll want to bring snacks and beverages as well. If you are driving you'll obviously be able to bring alot more items to keep his interest while he's not napping).
Make sure to take alot of pictures and/or videos. He won't remember the trip but you will and looking back over them over the years is priceless. It's amazing how fast the grow!
Don't over plan too much. Make sure to have alot of down time. WDW resorts have play areas for the kids as well as pools. My DD8 still loves to play in the playgrounds and swim.
Oh, and he should do fine in your room. As others have said, you can get a Pak n Play for free. Just set it up out of the way. One of my DD's favorite part of our trips is all of us sharing a room. She loves to be able to sleep in the same room as the adults. Oh, one more thought-if your DS has a special nightlite, etc. bring it and but it in the room. Also, for me, I like to sleep with a fan on, all the time. So I also bring a small fan that attaches to my headboard. It cools down the room and the white noise helps block out outside noises.
Oh, and one final thing (I promise) make sure to bring along at least one change of clothes (I bring water shoes/
crocs too) into the parks as there are places where kids (of all ages) can get wet. Even in October in can be hot.
Have a great trip!