Hi Wayne,
Caribbean Beach is an excellent choice! If you've never stayed at CB before, you might want to spend the time getting to know your resort that will be your home during your visit. I like to scout out bus stops & schedules so that I know where to go when I'm ready to go. There are several choices for dining & lots of recreation options including shopping, fishing, boating & biking. They have a 1.4 mile trail around the lake that is perfect for jogging, walking or biking. If you have kids, they will love hanging out in the arcade, along the beach areas or swimming in one of the resort's awesome pools. There are also playgrounds located on property if your are traveling with smaller kids.
One of my favorite things to do when I have a half day is to head to DTD for shopping & grabbing lunch. I have to purchase my new Disney additions to my wardrobe. Characters in Flight opened at DTD last spring & is super cool. Its a tethered helium balloon that takes guests up to 400 ft in the air depending on weather conditions. It offers an incredible view of the DTD area & beyond. Click
here for more information. Be sure to take your camera & binoculars.
Cirque du Soleil is currently performed Tuesday through Saturday at 6 p.m. and 9 p.m. so I don't think attending a performance will work with your 7:30 p.m. dinner reservation. A lot of the tours begin first thing in the morning so that would not leave you with many options there.
Whether I chose hanging out at my resort or DTD, I'd keep it low key & relaxing so that I am ready to hit the parks well rested & ready to go the next day. Hope you have a trip filled with magical memories!