I wouldn't use Ziplock bags--too much chance the zip comes undone and then the water leaks out leaving your fish very unhappy (who needs to be worrying about that when you're traveling?). I'd either individually bag the fish or, if they are really small and young yet and get along without incident ever, maybe 2 to a bag if the bag is big enough (shipping bags come in various sizes). The whole idea of individual bags--one of hte ideas at least--is so if one bag goes bad (fish dies in the bag, all the water leaks out, bag gets squashed, all the horrible things you hope you'll never have to experience but that sometimes do happen), at least you have the others so you won't lose them all. You probably won't need the Methlyene Blue since it's not an extremely long trip and they are young still.
Assuming the new water is fish-friendly, do the slow acclimation thing with all the bags--float the bags in the new tanks so the temp evens out, add a little of the new tank water to the bags over 15-30 mins or even longer if you want, just make sure to check on the fish to make sure none are reacting badly, make sure the bags are secure so air can get in (bags have a bad habit of collapsing when you don't want them to) but covered with a lid in case an eager fish tries to make a break for it, so the fish can adjust to the new water mixed in with the old slowly. Maybe even have a new bottle of spring water handy (that you can drink if the fish don't need it) just in case the fish do not react well to the new water even after slow acclimation. They most likely will unless the new water is really bad. When the acclimation process is done, I always pour the water in the bag (with the fish) through a net so the fish gets caught, then I put the fish into the tank and dump all of the bag water although I don't think it's critical after only 4-5 hours but why put used water into the tank.
