Bus Oaxaca to Morelia and  Guadalajara

Morelia is served by Primera Plus bus from Norte Terminal in 

Mexico City

Bus service from Oaxaca City is provided by ADO first class bus from the ADO first class station. about 10 blocks north of the Zocalo.  
Bus service from Oaxaca City to Norte terminal is available in the morning with one 9:30 trip and several trips at night.  The night bus is a good option because you can sleep during the trip and reach Norte Terminal in Mexico City early in the morning.  Ticket Price, 450 Pesos for the six hour trip
From Norte terminal, you can get a bus to Morelia and Guadalajara. 
Primera Plus is a good option for this trip.  Ticket Price on Primera Plus Bus is 340 Peso for the 3.5 hour trip to Morelia.

Primera Plus Bus and ADO Buses  use Terminal Norte in Mexico City

Morelia offers an historic center  with many colonial buildings  once owned by the church.  Find hotels around the Plaza.
The Hotel Historia is a good choice for its location and price.
Hotel Historia was once a elegant house located just off the Zocalo or main Plaza in Morelia. The hotel offers in-room wifi.

On Sunday the streets of Morelia around the main square are closed to auto traffic and given over to bicycles and pedestrians.

Primera Plus buses serve from Morelia and reach Guadalajara 

in about four hours.

Bus service from Moralia's terminal reaches many locations including the coastal resorts of Ixtapa and Zihuatanejo.  Buses reach Guadalajara from Morelia in about four hours.  

Bus Travel Chihuahua to Mexico City

Chihuahua, Mexico Bus

We reached Chihuahua at 7 PM.

      I left the Chihuahuenses to switch to an Omnibus. Chihuahueses does not put paper in the lavatories; Omnibus does. This is no big deal but it demonstrates that Chihuahuesesa has a low regard for the passengers that I find annoying. I had never ridden on Omnibus and wanted to check them out.

Copper Canyon train stop at Divisadero.  Train passenger get 15 minutes to
look out at the junction of three canyons  

Copper Canyon Trips

From Chihuahua you can get a bus to Copper Canyon for 240 pesos to the village of Creel in the high mountains at the edge of the Copper Canyon. The train is not the only option for a Copper Canyon visit.

see Copper Canyon options Copper Canyon Trips.  The Cuauhtemoc Bus makes 5 trips daily.

I left Chihuahua on an Omnibus at 8:00 PM after a burger dinner and settled in for the 12 hour trip to Zacatecas. (635 pesos)

I slept most of the night and arrived in Zacatecas at 9:00 AM, 8:00 Tucson time. I then booked a 10:45 Futura Bus for Mexico City Terminal Norte for 430 pesos.

Futura Buses are the best of the three: Futura, Chihuhuenses and Omnibus. They are each a good and convenient ride. Chihuahuenses does not provide paper in the lavatory (hardly a First Class attribute) and their bus was an older model frayed at the edges. Omnibus was running an older bus also but they did provide paper, took careful head counts, and had a well maintained lavatory.

The Futura bus did have paper in the lavatory and was the newest bus of the three.

Primera plus, a division of Flecha Amarilla, runs on the coastal route from Mazatlan to Mexico Norte and they run the best buses and best service for the long haul trip through Mexico, north of Mexico City.

Primera Plus runs luxury buses from Mazatlan on the Pacific Coast

 to Mexico City through Guadalajara  

I arrived at Mexico City's Terminal Norte and 8:00 PM and booked an ADO bus for Oaxaca,  leaving at 11 PM.
I have made this run before and I wanted to arrive in Oaxaca at dawn. ADO runs excellent service south of Mexico City. See ADO

I slept most of the way and arrived at 6:00 AM refreshed.
The total cost of the trip (excluding food) was around 160 USD including the Tucson/Douglas Shuttle. ($320 USD round Trip) Round trip air at the time was around $ 550 not counting taxi to and from the airport. (about $100 USD)
BUS-$340 USD including taxi transfer      AIR-$650 USD including taxi transfer.   (575 with a shared shuttle to Tucson Center)

Bus Service Mexico: Just Show Up. (Article)
The bus companies have web sites but they have for the most part opted for style rather than substance. They are full of razzle dazzle flash but lack function. With the exception of ADO and Primera Plus, they are not fully connected by computer and can not take bookings on the web.   That is not a problem. You just show up and there are so many options, so many lines and so many buses going in all directions that you seldom wait more than an hour, usually less. (Except at Christmas and Easter)
I usually stop in one or more cities for the night on a long trip like this. see Mazatlan,   Morelia,   Guadalajara,   San Louis Potosi,   Zacatecas, Chihuahua, Casas Grande, Alta Vista/Sombrerete

Estrella Blanca (Article) is a group of bus lines that serve 27 of Mexico's states. Lines include Futura, Futura Plus, Chihuahuenses, and Elite along with many more.

Mexico City Norte Bus Station

Mexico Norte terminal is a bus hub for trips north west and east primarily 

although ADO serves southern Mexico from Norte.  Buses from Norte 

terminal also serve to  Teotihuacan Ruin and Tula

Next: Eight Months Backpack By Bus to south America/Antartica