The buses from Chugchilán to Latacunga leave very early in the morning. I can’t remember if it was at 3am or 4am, but it was absolutely too early. Another option for me was to share a pickup with people who were going to Quilotoa, and take the bus at 13.00 from Quilotoa to Latacunga. A pickup from Chugchilán to Quilotoa cost $25 (July 2012) for up to five people. If there are more than five people everyone pays $5. The man with the pickup was maybe going on to Latacunga and then I could go with him for another $5.
When it was time to go it turned out there were many people going to Quilotoa, so they went with a small lorry. We were three who were going to Latacunga and we went with the man with the pickup. As the other two tourists hadn’t seen the landscape before and after Sigchos we went that way.
It took between 2-2.5h to go to Latacunga. The other two tourists wanted to go to the bus terminal so I went off there as well and walked to the hotel. We paid the driver $10 each.
Local Transportation is limited so timing is of the essence. Since schedules change, make sure you ask locals for the departure times. You can take the occassional bus from Latacunga, via Zumbahua, and Quilotoa or take the one going to Sigchos and from there another to Chugchilan. There are also trucks headed that way, specially milk-man trucks.