Tolling may come into play, I'm not sure if all states allow it but I do know NY does. Tolling is when you incurr a debt in one state and when you leave that state the SOL is frozen from the time you left.
As someone has posted it's a good question for an attorney as for if all states have tolling and if tolling is indefinite or such.
And yes there is no SOL on Student Loans.