If you can find your way there it is worth it it is a very pretty and low key archeological site.
It is a peaceful place with lots of history and great energy
Some parts are still being excavated. Others are waiting for more funding from the government.
It is beautiful, with lots of signs to indicate what is what.
Definitely hot so bring water and sunscreen.
To go by bus:
Antigua Central Caminario( may want to take a cab as it isn't that close to the center, i walked so it is doable but you need to keep asking for directions.
The 7th /8th booth ATE bus to Teuchitlan
It is between one and a half to 2 hrs ride. The buses are nice but local-108 pesos for a round trip. Buses run every 20 minutes
When you get there you can take a Taxi for 50 pesos each way or walk arguably for an hour (for new yorkers 40 min) to the site itself
Entry of 30 pesos includes the museum and a movie- very nicely kept and sweetly done. Gives you some background on the site.
No taxis to go back make sure someone is coming to pick you up unless you prefer to walk.
It's a nice trip outside the busy city.