3 years is a pretty long time to be a resident of Florida "temporarily" living in Pennsylvania. And in any case, even if you were a resident of Florida, you would owe PA tax on income earned in PA. As a resident of state B working temporarily in state A, you owe tax on a non-resident return to state A for income earned in state A. Then you owe a full year resident tax return in State B that reports all your income, with a credit for tax amounts paid in state A.
I doubt that filing a PA non-resident return would save you any tax over a resident return, and in fact you might be deprived of some credits.
In any case, the PA residency rules for tax returns are here http://www.revenue.pa.gov/FormsandPublications/FormsforIndividuals/Documents/Personal%20Income%20Tax...
