You can visit the Elysion by visiting NPC warp Captain Perbo which is located in Veherseba (X: 66, Y: 54).
Refer to image below. You must have [Premium Zone ticket] to enter as mentioned above or do the quest to receive a trial ticket.

To complete the quest, you need to collect items dropped by GreenTravel.
Green Turton shell

But remember, by doing the quest, you are now allowed to visit higher levels of Elysion.

After talking to NPC, it will give you a limited ticket of elysion (1 day if you did quest or the same time as your premium zone ticket):
Aerobomber Ticket


NPC Location: