Robert, I think you should opt for the 70-300 instead of the 50-200 + 1.4 for your trip. If the overall image quality difference is only marginal, and portability is important, and you'll only be using a monopod, the 70-300 is a better choice, I think.
I've always felt that when talking about a comparison between any two objects (lenses, cameras, televisions, etc), often both are perfectly fine judged on their own, but it is only the direct comparison that shows subtle differences. I'm not saying it isn't a valid idea to compare things (it is), but now that you have established that the 70-300 is a fine lens, you should forget about the marginal differences and use whichever lens is appropriate for a given situation. In the case of your trip, all the other factors point to the 70-300 over the 50-200 + 1.4.
Plus, of course, you might even want to pack the converter, just in case you need it...