Henry Doorly Zoo it is!
just did that, I am sure SD has you up to speed on protips but my advice is the best stuff is the in the buildings (Aquarium, Rain Forrest building, the alligators in the basement of the dome) and the outside stuff is pretty meh.
I won't waste a nice weather weekend on it again but will probably return for one of those rando long weekends when the kids don't have school.
Also, the Courtyard downtown has a pretty good location (the Local Bar across the street has like 25 NE brewed taps
and 4 foot tall Connect 4 along the wall) but the actual hotel is well worn.
I would do the Hilton Garden Inn next door if only for the fact it has a hot tub and the Courtyard does not.