Okay so in the trailer, when Sora and Riku are on the island talking, Sora asks Riku about how far a raft can take them, do you think that maybe in this game there are no gummi ships, but this is about what would of happend if they did take a raft? Like they were supposed to in the first game?

no it's about the mark of mastery exam they take. If they'd taken the raft then they'd most likely have just said around their world and landed on the island again.

interesting. ^this. a raft can't take them anywhere, they're just reliving kh1 memories

If they'd taken the raft, they would have died of starvation. They took barely any supplies.