If it was overcast, you still get tanned. If it was raining, you still get tanned. Win win, right?
Trinidad, for me, was not overly 'Caribbean', its a built up city with a lot of hustle and bustle, its quite busy and heavily populated for an Island. It was so lovely to drive around Trinidad and see all the little different coloured houses, and the men sitting outside watching the world go by with a beer (or rum!) If you drive further out there are some pretty beaches. If i'm honest, i didn't spend a lot of time in Trinidad when I first arrived.
Tobago, on the other hand, is beautiful. If you're looking for palm tree's/coconuts and white sand, then then this is your place! You could easily drive the length of Tobago in a day, if you get up early enough. Its absolutely breath taking.