Linda & Larry,
I recommend Vina del Mar over Valparaiso for a stay. It's a suburb and Valparaiso & the port are a short taxi ride. More to see & do in Vina. If you haven't spent time in Santiago, it might be worth a couple of days there and then time in Vina if you have free time to spare. We'll be in Vina del mar for a few days before Koala.
Jim & Pat