Sharper, lighter, bigger max aperture generally.

The 14-24, 24-70, 70-200, and 200-400 (speaking in Nikon, I suspect other brands are similar) are pretty much the only zooms that'll hang with a prime sharpness wise.

The rest are all compromises in some way.

Back to the subject at hand, I'd hate to ruin a shot on a once in a lifetime trip because I left something at home.

I'd bring all my lenses and tripod/monopod as well and work out a solution to get it from A to B.

One exception to this is redundant glass. If there's a zoom and a prime that cover the same focal length, I'd bring the zoom and leave the prime, unless I had a very specific reason for wanting the prime. Zoom is definitely more flexible, and for a once in a lifetime trip like that, I want to cover as many possibilities as possible.

I'll recommend bringing weather protection for the gear as well as getting good at lens changes under cover. If you're taking splash or spray or rain and you still need to swap lenses it *can* be done, if you've practiced it ahead of time. Duck under a rain coat or a tarp or something, do a quick swap, stow away the spare, get back to shooting.

This, of course, is one advantage of the pro zooms, they're a lot more weather resistant than kit glass and can save you a few lens changes.