We just returned from the 7 day western with two 2- year olds and a nine year old.
Definitely check the navigators every day for open house times at the Oceans Club so you can take your little one into the club to play. Also look for "Toddler Time" and Wake up with Disney Jr., etc- great for toddlers. My two LOVED the moving portraits, located all over the ship. They also loved hanging out in the atrium before dinner and dancing to the live music.
In the room they slept on the pull out couch (one in each of our connecting rooms, they didn't share a bed) with a guard rail and they did great. The beds have their own light over them too, which of course they liked to switch on and off. We also brought a white noise machine to help when they went to bed, so we didn't have to tip toe around quite as much.
As for food, the twins are used to having small snacks throughout the day, and even though there is TONS of food on the ship, there isn't really any toddler snack food. Mine got tired of french fries, and we could only let them have so much ice cream. We were really happy we brought some snacks from home- fruit pouches, crackers, yogurt melts, granola bars, cheerios, etc. If you plan ahead, you can also grab extra fruit or yogurt at bfast and save it in your fridge for a snack later

Also, don't forget that the servers at dinner are VERY good at helping you out if your kids like certain foods that aren't on the menu. Always ask, because usually the answer will be yes. We asked for spaghetti, white rice, applesauce, etc , none of which were on the menu, but they said no problem! Also my 2 year old ate a baked potato two nights in a row, haha