Bardeelus, Driola, Kaya and Audera were in a simple word, amped with power. Their magical abilities have reached new heights, they were more powerful than they ever were, and this power went beyond magic as well!
Sure they may not be able to kill a royal demonic god, for example, but they were still pretty strong. In terms of physical strength, when the situation demanded it, they did not get tired at all.
The red air fueled them with strength, so they could toggle their physical energy upon will. They slept only when they wanted to, and if the circumstances demanded it, they could walk or run for kilometers at a time without getting tired.
With that advantage considered, they walked for two days and two nights straight. At that pace, they managed to reach the ruins of Gurlich, under the aforementioned time bracket. If Erdeta was around, they would have gotten to the ruins within an hour, but this result wasn't so bad either.