Mary, if you are well-traveled and have traveled alone by yourself before, you’ll be fine, although of course you’ll have to be more vigilant in the cities. Don’t walk alone at night and even during daylight, don’t wear flashy jewelry or carry an expensive camera out in the open – -common sense stuff anywhere in the world.
I’d suggest you look at http://www.ecuadorexpatjourneys.com/ They do great tours and if they don’t have one scheduled on your dates, they can put a personalized tour together for you. One of the owners, Sarah Dettman, speaks at IL conferences and she is a friend. You can email her directly at s.dettman@yahoo.com.