Not my favourite Port of call. We took an expensive open top bus. We were told that we could get on and off as we pleased but once we got off could never get back on as all buses were full. Driver did make room for somebody who had not yet bought a ticket though and relieved him of his Euros. Another passenger told me he had seen the same thing.
Royal palace is well worth a visit and almost everything worth seeing is within walking distance of the port. If you have walking difficulties I would suggest using a taxi. I spoke to someone that had rented one of the electric golf buggy type cars by the quayside and apparently though he could get everywhere he couldn't park.