The metro of Mexico is a great way to get around for 3 Pesos (0.20 $US) until midnight. Minibuses are 2.50 for the first 5km, 3 Pesos 5-12km and 4 Pesos above.
EAST: Autopista Puebla
Take the metro line A towards La Paz. You can get off either at stop santa martha (2 stops before the last stop) and you are on the road wich turns into the autopista to puebla. If you want to get further out of the urban area you can also get of at the last stop la paz and invest there 6 pesos into a microbus towards chalco. Ask to be dropped at the toll gate (Caseta de Cobro). After a 20 min ride you will be dropped at the autopista, walk 500m an you´ll reach the big toll gate. No touble with police here, if you walk and hitch on the autopista. Make sure to take your ID with you though. There is a military post at the toll gate. They may check you. If you enter Mexico that way ask to be dropped at a metro station. Most probably you will pass the station "blvd puerto aereo" while entering the city.
WEST: Autopista Toluca
Take the pink line (line 1) to Observatorio (last station). Near by there is a big bus station for "Autobuses Foráneos," the buses that take you to other cities. On the other side of the subway station, there is a more informal bus stop where the local buses run. Look for the bus that says Caseta/La Marquesa.
It's important to tell the driver you want to get off before the toll (caseta), otherwise you will end up in La Marquesa.
You can hitchhike near the toll without problems. The security guards might tell you to move if they think you're too close, but they just need you to step a couple meter back. If you do end up in La Marquesa, you can always ask the people who are eating quesadillas at the little food stands to give you a ride. Almost all of them will be going to Toluca.
You can take the autopista or the beautiful carretera a Cuernavaca, if you leave the city via carretera you can (if the weather is fine) overlook the whole city. Both roads begin at the end of Tlalpan. One way to get there is from metrobus last station "Doctor Galvez". The metrobus runs down the long north south road "insurgentes". You need a card (which costs about 11 pesos including 1 ride) to take the metrobus, but if you ask, people will let you use their card for 3.50 pesos. From Doctor Galvez a minibus runs to the point where autopista and carretera split. You can take another minibus to the toll gate (caseta de cobro) de la autopista.
Querétaro and United States: take a metro to Buenavista where you take another suburban train (note that special card is required to go on it). Take the suburban (15 pesos) all the way to the last stop at Cuautitlan (I think they are building an extension of the line) and get off at the left side of the track. Cuautitlan is one of the side cities of metropolitan Mexico. The caseta (toll gate) going north is about 7-8km from here. In Cuautitlan you can ask around for the main square or the main road "De Guadelupe" which goes towards the highway. Somewhere here you can find buses (8 pesos) or minibuses going to the caseta (toll gate). Ask around. Note, the bus follows the highway, but it doesnt pass the toll gate. Just few hundred meters before the caseta the buses turns in to some other town and you have to jump off. But then its easy, you have only 5 minutes walk (you can see the toll gate from when the bus turns). Its a main toll gate north of of Mexico, so you might have company of some other mexican hitchhikers :)
P.s. I think you can get on buses going towards the caseta from the suburban train station of Lecheria (just a few stops before the Cuautitlan). Didnt checked it myself though.
Pachuca: From metro station "Indios verdes" take a minibus to autopista, or toll gate.
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