As we were spending a few days in Campeche, it didn't make sense to rent a car. We took the ADO or Autobuses de Oriente to get from Merida to Campeche. The ADO offers first class service between principal cities. The buses are comfortable, even for 6' 3" guys like me. Seats are reserved when you purchase the tickets, and the buses have air conditioning washrooms and even an on-board movie.
In 2006 we paid 214 pesos (about $20US) for a round-trip ticket from Merida to Campeche.
Mexican Federal Highway 180 is a Mexican Federal Highway that follows north through Campeche into Mérida, and finally east into Cancún.
We take it to get to Uxmal Mayan Ruins from Campeche.
The Royal Highway was the road used to link the two most important peninsular cities, Campeche and Merida during the Spanish conquest.
You can watch my 1 min59 sec Video Mexico Campeche-Uxmal out of my Youtube channel or here on VT.
You can watch my photo of Campeche on the Google Earth according to the following coordinates 19° 50' 46.01" N 90° 32' 15.40" W or on my Google Earth Panoramio San Francisco de Campeche 2.
The 1st class ADO terminal is not right in town, however it's easy to get in. Just go out the front of the terminal, cross the road and keep walking straight for about 200m. You will see a bus shelter, and lots of local buses come along to take you into town, costs 5.5 pesos.
When coming from ADO into town, almost everyone will get out at the market. However if you stay on the bus, it continues down to the waterfront from where you can access the old town through the Sea Gate.
Combis leave from the markets in Campeche to Edzna. There is a street between the market and the Alameda park, the combis are blue and you will see a sign showing where they leave from, or just ask. There are also public buses which I was told left at 7am, 9am & 11am, the buses would be marked Pich, or Bonfilo.
The combi I caught left at 10.30am on a Sunday, took about 45 mins and dropped us off just near the entrance.
Coming back they passed about every hour with the last one at 4pm. Cost 30 pesos each way