However, for most of the 4 year rental (minus 2 months) the SC rental was my only owned property (I only received rental income with the SC property as my "second" property for 2months). Help!
Doesn't matter. That property was "NOT" your primary residence for at least two of the 5 years you owned it, counting backwards from the closing date of the sale. So you will pay taxes on 100% of the gain.
Even if you never rented it out and it sat vacant for the entire time, it was still not your primary residence for 2 of the last 5 years you owned it.
