Ecuador itinerary for family with young kids?

We'll be traveling to Ecuador in July for around 10 days with our three kids ages 10, 8 and 6. We won't be doing Galapagos on this trip ($$$). Would like to get some exposure to Andes, Ecuadorean culture, coastline, etc. I'm thinking of doing old town in Quito, Otavalo area and market, Banos (and Ave. of Volcanos), Isla de la Plata (poor man's Galapagos) and the Machalilla Nat. Park to see whales, etc. Not sure if these are best places to consider. Any suggestions on must do activities to do or places to see with kids or good places to stay that provide a good launching pad for the area(s)? I have also considered the Tren Crucero, but it's not cheap (is it worth it?). Also, given our short stay I'm wondering if renting a car for some of the stretches is wise or if hiring a driver would be better. I speak Spanish and traveled a lot in S. America in my younger days, but I've never been to Ecuador. Thank you for any ideas.....Roby