Arriving in Puerto Vallarta on Dec 21 and departing PV on Jan 6, me and some friends are doing a mini Mexico trip. Ideas of places we are interested in staying are PV (obviously), Guadalajara, Guanajuato, San Migel de Allende, Mexico City, and Morelia. We are young and energetic, and enjoy the outdoors as well as city life. I was thinking of an itinerary somewhat like this:

4 nights Puerto Vallarta (4 at start of trip and 2 at end)
3 nights Guadalajara
2 nights Guanajuato
4 nights Mexico City
1 night Morelia
2 nights Puerto Vallarta

This doesn't really give us any time to daytrip from these places (exception Teotihuacan), but should give enough time to take in each places major sites and a bit of their feel. The night in Morelia I think will be nice because it breaks up the long, long bus ride from Mexico City to PV into two more reasonable rides.

Sounds fantastic to me! As long as you realize the length of some of the bus rides (as you mentioned) would have been my only possible negative comment. Puerto Vallarta is one of my personal favorites and should make a great place to start and end the trip.

If you haven't yet you might read or post on Lonely Planet's BB as well. They've got some great young posters there with bus/Mexico/itinerary experience.

Very nice itinerary - you're covering a lot of territory. I've been to all those places, but not all on the same trip. I think 1 night in Morelia is a little short - there's a lot to see there, and Patzcuaro makes a nice day trip from there. I'm not sure how long it takes to go from Morelia to PV - that bus ride could be a big long. But there are some very nice bus lines in Mexico, so it could be quite comfortable. Between PV and Guadalajara, it'll be about 5 hours. Between Guanajuato and Mexico City, I'm thinking it would be about the same. I'm nt sure about the distance bween Guadalajara and Guanajuato. You could be spending a fair amount of time on buses. A good site for bus information is ticketbus.com.mx.

RAR,
I'm not a fan of PVR nor Guadalajara.
ETN and Primera Plus are the two major bus lines serving Central MX. They have web sites with schedules and fares. Their first class seats recline completely and are great for night trips.
It's just over 4 hours from Guadalajara to Guanajuato and about 1 hour from GTO to SMdA. I would suggest you take the local bus from GTO to SMdA and stop in Dolores Hildalgo and Atotonilco on the way.
It's about 4 hrs from SMdA to MEX.
One night in Morelia may be too little.
I would consider Oaxaca as well as I'm not a beach freak (poster boy for sun induced skin CA and Melanoma).
M

Thanks for the ideas