To sell or not? If sell what to do with the cash?

[Account Closed]

My sister and I inherited. 4 individual commercial properties all leased to Dollar General. They have about 10yrs left on their leases NN. Rent is $16,500 per month. The loan payment is $12,700 ,roughly 1.5 million left on the note.  It balloons in December 2016, my sister wants out and I honestly would prefer to not be in business with family. I spoke with a broker he said they could bring anywhere from 2.3 to 3 million. I'm rough estimating, I could walk with 200-300k. I'm 24 years old and I love working with commercial real estate and me and my wife would like to start my our own real estate holding company one day. I also currently have a 300k mortgage on my house, I've considered paying it off  with the sale proceeds if there's enough and saving each month what I was paying in a mortgage payment. The interest rate on my mortgage is 4.75% with 29 years left.  After I've saved for a couple years we start buying up some properties for ourselves. Or do we use that capital to start buying now? Looking for advice and opinions! Thanks!