Well for Tunis I really enjoyed the Roman Baths (a UNESCO World Heritage Site) ... but hated the Souks, it was a mazelike high pressure flea market where they hold you captive in a rug store before taking you around to the other vendors. I would imagine it would be possible to book an english speaking tour (French is much more common there) to just the Baths. I also understand there is some outstanding wine coming out of this region, which is very strange since it is a muslim country. When you come off the ship you will likely see some exotic livestock as they usually have a camel or two out there for pictures and rides.
Check the ship's excursions for Savona and see if they still have "The Palaces and Principalities of Monacco. It is a fantastic tour and I know we had at least a busload of English speakers on our tour. It is fantastic for anyone who is interested in Formula One Racing, Grace Kelly (Princess Grace), Prince Ranier, their Children, Tour the Cathedral where they were married and are now entombed, See the Palace, Visit Monte Carlo, See the Olive Groves, The Italian Alps in the distance. The hundreds of tunnels through the mountains. It is really a wonderful way to spend a day.
Hope that helps.