gummi

Okay, part one.

Did anyone other than me hate the gummi ship with a passion? It was my least favourite part, and it looked rushed and the graphics were crap compared to the rest of the game.

Part two.

Was it going to be possible to get to the Disney Castle before KH1 was released and was it cut out for time?

The gummi ship could have been good, but it needed re-vamping, which it is in KHII.
No, you couln't get to Disney Castle in the oirigional. At least, not in the non-japanese versions.