The Wonderland Board

Hi
I have finished about 20 levels, but now find myself with no place left to go. There is one rainbow "portal" working between Barren and Star City, but all the rainbow gates are up. In one of the conversations with Hawking, he mentioned that Hubble has the rainbow keys. Where is he?
Any help, ideas, etc. would be greatly appreciated.

Thanks in advance....
Anton

People keep asking about this part, but it's actually very easy. Just talk to Hawking but ask EVERY possible question. He will then open up a bridge for you.