Well, if you want to do a little last minute "training" before going on the cruise - I would say Jambo House with nice, long, multiple-trip to the buffet dinner at Boma ...

... followed by a relaxing rock on one of the (deck) chairs on Arusha Rock ...
... now, if you want to walk off that Boma dinner (assuming you can walk afterwards ...), then Kidani ...
BTW - be prepared to fall in love (and awe) with AKV ...