I think I would like to take a peek at the locks since you will be transiting through them the next day. The locks are well lit at night and you will be able to see a great deal. I am always a bit apprehensive in recommending things since I know where my interest lie and my interests may not be the same as yours
Colonial Panama would be attractive at night but I really am not sure if it would be as good as would in the day.... just an observation not a recommendation for or against.
Flamenco is the outermost island on the Causeway, depending on where you actually get to go on the island, a there may be a really great view of the city or the bay. This tour appears to stay fairly close to where the tenders put you ashore, so I don't know how much sightseeing will be available to and from the tour.
"If the phone doesn't ring, it's me!"
"Is it ignorance or is it apathy? ... I don't know and I don't care!"
S.S. Badger R/T from Manitowoc June 02