Personally, I'd say GO FOR IT.

I did the "treechange" in my early 20s, sure it was only to Shepparton, but it was awesome. I still have many good friends up there and would still be there, circumstances permitting.

It's not as far as Shepparton, I used to do Melbourne and back in a day. Driving becomes part of your lifestyle, so whilst you will be spending less on other things, you will be spending more on petrol. But you have LOCAL shops, where you know the LOCAL people, and you will be part of a LOCAL community. Melbourne doesn't have that AFAIK.

Financially it appears to make sense. And DSD won't be able to "stay out" whenever she likes as the country isn't as "fun". As long as she falls in with a good crowd, she'll be fine.

Good luck making your choice!