I found it difficult to find information on the internet, on how to get to the Migration site. I am not sure if there are airports in Mexico City or Morelia, but if you can get to Angangueo from there, you are going to save yourself a lot of time.
The total time for us, from Acapulco, was 14 hours, and three buses to Angangueo. After that there was the hour ride up the mountain, and the hour walk up from there.
Your total time from Acapulco, (if you don't miss your bus) is 2 1/2 days.
It is a long trip, but if that is the only way you can do it, it is still worth it.
Fondest memory: Why the Monarch's, of course!!
Favorite thing: Angangueo makes a great base for visiting the butterfly reserve, but does not deserve more than a night's stay. We arrived in the town in the late afternoon, had a stroll in the plaza and up and down the main street and had seen it all. In the morning we made our trek to the butterflies and then came down for lunch and caught a bus out of town.
Let's face it - there is nothing to do in Angangueo. The village is built around a main street practically devoid of shops. There is no monument worthwhile to see and no interesting walks.
The best strategy is to arrive in Angangueo in the early evening, have dinner, sleep early and well - and be ready to wake up at 7AM to go see the butterflies.