My dad has a car that is 4 years old, it is a subaru outback, with 200,000+miles on it (not a typo, he drives it all over the eastern coast). Now would the subarus insurance cost(total) be lower than if i bought my own used car?
It is not true. The insurance companies use a number of formulas to calculate cost and it is not unlikely that an older "risky" model would have a higher insurance cost than a newer "safer" model. You will also quickly find that they do not like to share this information. Years ago, insurance symbols were included in the NADA books. They quit listing it after the insurance companies stopped sharing this information.
The best way to check is to just call your Agent and ask about the different cars you are considering. You might also find the info below of interest.
http://www.iihs.org/brochures/ictl/ictl.html