Center Console Boats And More

Can I drive my car to Cuba, and then back to America? Do I need special permits?

I'm building a lightweight floatation platform, sort of like a pontoon boat, except the pontoons fold up really tight so the thing can be easily towed behind my Toyota Matrix. (trailer/pontoon has fold-up trailer wheels).

I've tested a 1/10 scale model and it works fine, so I'm building the full sized model now.

I want to tow it to boat launches in Florida, and then use it to go to the Bahamas, Cuba, and many other places, and then actually drive around these islands (towing my trailer) instead of just seeing the areas around the harbor.

But, If I do travel to Cuba or Bahamas, do I need any special licence plates or government paperwork to allow me to simply just drive around with the locals?

And in this economy, do you think that visiting this way would be safe? I just read a story of how tourists in Mexico are being beat up just for the money they are carrying with them. So with everyone getting laid off, is it still safe to be a tourist, or would I come face to face with a guy with a gun, asking for me to hand him the keys to my car?