Well, actually the final destination is going to be HOU. I'm doing this as a leisure travel thing...I'd like to maximize miles as a bonus, but that's not the main objective.

Here's the basic story: I'm in Antarctica right now working at a research base. When I get out I get dropped off in CHC with a fare credit back home that makes my 4 continent trip (economy class) about $1600 USD. My home base is HOU, so that's why I need to end up there. The LAS part is for a friend's bachelor party, so that has to stay. The DFW-HOU is only a quick stop so that I can take the LSAT on Feb 12th, before I try to use the rest of my segments. As far as the alliance needs to know I'm making my way overland to LAX, so no flights actually have to end up there. I can get a round trip DFW-HOU-DFW for about $120 USD, so there's no point in wasting two segments for that. If I need to buy additional segments at whatever the cost is, that might be a good option.

What are the best destinations in the Carribean that would use my remaining segments to the best advantage, returning me to DFW, IAH, or HOU? An additional bonus would be if they had easy access to Havana, off network of course.