You could take the boat to POR and then a bus from POR to MK. However, all of this sounds really slow. You might really consider the cab. However, don't be surprised if it's not as cheap as you thought it should be. We took a cab from the Poly to AK to eat at Jiko. I think it was over $20 or about that with tip. Everything seems so close together, that I thought it would be ~$10.