As for Cuba, it is actually a quite simple trip. I have a good friend that just went last month with his family in his 310. File IFR, do normal paperwork and go. He said it is a pain going through customs and stuff simply because, well, they don't get many visitors, but he said it was no big deal at all. He also said not to hire a company to do the paperwork for you because there isn't much to do.
If anyone is interested in going let me know and I can put you in touch with him.
Glenn