Your schedule is likely Boarding day - sea day - CC day - Nassau Day - CC day - Debarking day (morning!)
Your second night is likely to be formal ("dress up"). There will be a lot of cruisers who participate in dress up, so if you like that, it would be a good evening to eat in the main dining rooms (MDR).
I might suggest Palo for the first evening. You are most likely to get a good seating time, and it's a great way to start off the cruise. Please stop by the dining room and tell your waiters you won't be there…too many cruisers show up late, and those great folks are worried when you don't show and telling them you're not coming will be a wonderful courtesy. Trust me, they will appreciate it.
And, brunch at Palo if you can snag one on sea day! Get a late time, since you'll be full if you ate there the evening before.
Here's a navigator from last year:
http://disneycruiselineblog.com/201...ise-on-disney-dream-itinerary-a-june-26-2015/