ANU's campus is lovely (I plan on either transferring or spending a year there). ACT may not be the most interesting place to live but if you're really involved in campus life/extra-curriculars, it makes up for it (which is expected from a Tuckwell Scholars haha).
Just apply for the scholarship. You lose nothing from doing so (I was in a similar position last year, where I was hesitant about applying because my achievements weren't flashy), if you get it and decide that ANU is not for you, you can reject the scholarship (I know someone that moved to Cambridge after spending a semester at ANU on a Tuckwell's scholarship). If you apply though, make sure that you know why you want the scholarship (not just because you would like to experience interstate life, why ANU in particular?) and how you think that you epitomize the values of the scholarship.