I figure you wory too much about Mandarin learning environment. Almost any place in Taiwan, you may use mandarin to communicate with anyone who is under 60 years old. The problem is if there is enough education system to facilitate and support your Chinese learning. To learn a language well does not call for a favorable practice environment only. A good well-organized lesson is still quite important for your learning indeed. My opinion is once you have engaged in some programs of Mandarin learning in some university or education institution, you may get essential information to improve and practice your Mandarin effectively.
If you want to learn and practice with a free competent Chinese teacher, inform me by text.