While staying in Puebla my wife and I made a day trip to Cantona about 90 km NE of Puebla more-or-less using public transporation.
Although generally not described in travel books, the site is very impressive and unfortunately does not receive many visitors. For almost all of the 3 hours that we were there on a Friday, we saw no one else.
From down town Puebla, here is what we did.
-taxi to CAPU bus station
-"Via" bus line to Oriental - about 70 peso each and about 90 minutes on local highway 129.
-exit the bus in "centro"
-taxis were right there
-"chartered" a taxi to take us to Cantona, taxi stayed for 3 hours (it takes more-or-less 3 hours to walk the site) then return to Cantona.
-english speaking guide (he spent 1.5 years in Calgary and his English is quite good) firstname.lastname@example.org
-"Via" bus back to Puebla from Oriental centro - at an estimated 30 minute intervals.
-total door to door time - 8 hours - total cost about 1,000 peso
The site is much different than the well descibed and well visted Monte Alban, Teotiuacan, and Chichen Itza, etc, with many comparatively low pyramides and many ball courts on a quite large site.
For a group of 4 persons, hiring a taxi for the day in Puebla would probably make more sense, since the bus fare for the two of us cost about 300 peso, and would have the advantage of going by the faster toll highway.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC