Central Sierra itinerary and transport options


My husband and I are travelling to Ecuador on Sunday 26 August, returning to the UK on 23 September (4 weeks exactly). I have planned the start and end sections of our trip and I'm happy with them. For the bit in the middle, our plan is to travel down the central sierra from Quito to Cuenca, then on to Guayaquil to connect with our flight to the Galapagos Islands. What I am struggling with is trying to apportion the time we have (7nights) to each of the places I think we might want to visit in the central/southern sierra. The stopping off points could be:

(i) Banos de Agua Santa (for thermal pools, swing at the end of the world, ziplining and la Ruta de las Cascadas)

(ii) Riobamba (for Chimborazo)

(iii) Cuenca (for architecture, Ingapirca, thermal pools, shopping and relaxing)

Would 2 nights in Banos, 2 nights in Riobamba and 3 nights in Cuenca be a sensible apportionment of time? Or do any of these places merit a longer/shorter stay? I should say that neither of us are avid hikers but we do appreciate stunning scenery, so actually seeing the volcanoes would be good enough for us. We don't need to hike or climb. And we are not interested in El Nariz del Diablo train.

As far as how to travel down the central sierra, we would rather pay for a car and driver than use the buses. So, if we followed the itinerary above (Banos 2 nights, Riobamba 2 nights, Cuenca 3 nights, then to Guayaquil) would it make sense to hire a separate car and driver for each leg of the journey, so that we would not be paying for a driver to hang around for 2 or 3 nights in each place? So we would have:

Driver 1: Quito to Banos

Driver 2: Banos to Riobamba

Driver 3: Riobamba to Cuenca

Driver 4: Cuenca to Guayaquil

On this, can someone please give me a current indicative daily rate for a car and driver? I have seen posts that seem to suggest $160-$180 per day. Is that current and correct?

I also note that we could fly from Cuenca to Guayaquil (via Quito) for a reasonable price and it would take the same amount of time as it would take to drive. Any thoughts on that option? Would we lose out on seeing worthwhile landscape/stopping off points if we take a flight or would we gain something by seeing the volcanoes from above?

I'd appreciate any input from those with relevant knowledge.

Our complete itinerary is:

Day 1: Arrive Quito. Overnight at hotel near the airport

Day 2: Fly to Coca. 4 nights at Lodge

Day 3: Lodge

Day 4: Lodge

Day 5: Lodge

Day 6: Lodge to Coca. Flight to Quito for 4 nights.

Day 7: Quito (go to Otavalo for Yamor Fiesta and Saturday market)

Day 8: Quito

Day 9: Quito

Day 10: Quito to central sierra/southern sierra for 7 nights

Day 11: central sierra

Day 12: central sierra

Day 13: central sierra

Day 14: central/southern sierra

Day 15: central/southern sierra

Day 16: central/southern sierra

Day 17: southern sierra to Guayaquil

Day 18: Guayaquil to Galapagos

Day 19: Galapagos

Day 20: Galapagos

Day 21: Galapagos

Day 22: Galapagos

Day 23: Galapagos

Day 24: Galapagos

Day 25: Galapagos

Day 26: Galapagos

Day 27: Galapagos

Day 28: Galapagos to Guayaquil. Overnight in Guayaquil.

Day 29: Flight Guayaquil to UK

Many thanks