I've been using Duolingo to learn Turkish. It isn't really meant for light learning for travel, and has a specific order that is used when introducing content, and you cannot skip topics in order to reach the lesson on travel. Also it takes many, many lessons before you will reach the one entitled "Travel". What is easier and more to the point is a great list of words and phrases that are specifically prepared for travel, located at WikiTravel. It will meet most of your travel needs without requiring nearly as much time. Since I've completed quite a bit of Duolingo already, I feel the information at wikitravel is better for those who just want to learn enough for a trip. It is located at https://wikitravel.org/en/Turkish_phrasebook . I'll copy the page's content to my phone so that I have it in case I have trouble accessing the internet.
I am preparing for the tour that starts on 4/22/2019.