Can´t travel to Dessert bloom park

It‘s easy;

Select Travel on the phone;
Travel to Oasis Springs in the park, and search for the cave. 
This will allow you to complete the quest.

Tip: Complete the optional quest first, otherwise you won‘t be able to redeem all event rewards. 

When you press the M key for your sim to travel, are you able to select for your sim to travel to Desert Bloom Park in Oasis Springs? If you are, then when  your sim arrives at the Park you can then get them to go to the cave and complete the task by breaking it and exploring it.

No, it's not that easy. I do not own extension pack which would allow me to travel there. In this event there is a special button to travel specifically to Dessert bloom park. That button is missing and I can not finish the quest.

I do not own the extension pack so I can not travel to Oasis Springs. 

Oasis Springs is a base game world. It comes with the base game Sims 4 and didn’t come with an expansion pack.

Oasis Springs is Base Game.

You don't need any expansion pack to travel to  Dessert bloom park. It's in the basegame.

For those having problems, you have to go to Oasis Springs and manually travel to the park to open the cave to the grotto. Hopefully this helps some of yall!