San Miquel de Allende trip from Zihuatanejo

Has anyone taken the bus from Zihuatanejo to Celaya and then a bus/taxi from Celaya to San Miquel de Allende?
I don't want to drive.
Flying is an option but it seems like a lot of moving parts for one day.
I saw this bus trip into Celaya from Zihuatanejo -about 5 1/2 hrs -and then another hour from Celaya to SMA by taxi. Wondering if anyone has done it? Thanks!

I did that route maybe 3-4 years ago.
Changed buses in Morelia.
And then waited an hour or two in Celaya to catch bus into San Miguel.
Remember chatting with a couple of students who were going to Medical School in Celaya.
I got into San Miguel de Allende at about 9PM.