We have been through the canal twice. The last time we were not permitted to leave the dock area in Panama City due to violence in the city.
We have found that you get a very good view of the canals and the locks from the ship. Of course you do not see any behind the scenes events, if any. You can see the electic engines and cables that pull the ships through the locks and full views of the lock gates.
There are many photo opportunities during the hours it takes to traverse the canal. In the background, on the speaker system they will have a local expert tell you about the area you are taveling through and its history. In addition, on the room TV they will continually play the story and history of the building of the canal.
We did not take the RR or other day trip in the canal, so I have no comment on that to help you.
So, I suggest walk about on the decks, take photos and enjoy a cool drink as you pass through the canal.