None of this information is true but for the sake of argument say I am a California resident. Then say I attend a university in Indiana as an out of state student for 4 years. If I then go on to attend a public med school in Indiana after my undergrad would I be considered instate or out of state for tuition purposes?
Out of state for both admission and tuition purposes in all but a handful of states.
OOS
There are sometimes things you can do to establish residency during your undergrad years. My father became a California resident for tuition purposes while he was at UC Berkeley. You would have to look into the process for the specific state; it might also depend on your age and level of financial independence.
You would have to check each university for its policies. At many, you would not qualify unless you have been living there without being enrolled full-time at college for an established time period. Each state is different, though. PA is more restrictive than NJ, for example. They might have different policies for students entering a graduate professional school from a public university within that state.
How can you establish residency? Do you have to buy property?
Residency requirements have changed in the last couple of decades. What one’s father was able to do will not apply now. Check each school for the residency requirements. They have different policies.