They were all using steed. The most impressive steed was, of course, Jack's nightmare. Kabaka and the others were flabbergasted when Jack summoned Pandora. Most of them rode a distance away from Jack since their steeds refused to be anywhere near Pandora.
Jack could have arrived at the destination faster if he used Pandora's full speed, but he adjusted to the others' pace.
Pandora's presence helped smoothen their journey since no monsters dared to approach. Even so, it was already the morning of the next day when they finally arrived.
The place was a fort by the mountainside. A soldier on the wall saw their approach and notified the others. The gate to the fort was soon opened.
After entering, Jack saw a familiar sealing dome at the center of the fort. He did not doubt the underworld portal was inside that dome.