As others have stated this can be a bit of a glitchy achievement. I finished the storyline and also found all of the "secrets" in the game and still didn't unlock this.
All you actually need to do is visit the 3 hotels in the game. Find the landing point on the building, hit
to get off the boat and onto the hotel and if you've got the achievement app pinned you will see the progress bar fill up by one third. The hotels are 3 of the red blobs on the following map.
1. The Lyonesse Hotel - located right next to your home base (the white blob just below centre screen) you visit this as part of the tutorial.
2. The Villdyse Hotel - slightly south east of home base.
3. The Rullyeh Hotel - found in the north east corner of the map.
I've tested this with another profile and you can pop this achievement at any time. This can be done within 10 minutes of starting the game if you're in a hurry. If you're having problems unlocking this achievement just visit these 3 locations.