The passenger bus is the king of the Mexican road. Several lines connect major destinations in the Puerto Vallarta  region, both with each other and with the rest of Mexico.
Three distinct levels of intercity service—luxury-class, first-class, and second-class—are generally available. Luxury-class (called something like “Primera Plus,” or “Ejecutivo” depending upon the line) service speeds passengers between the major destinations of Puerto Vallarta, Tepic, and Barra de Navidad, with few stops en route. In exchange for relatively high fares (about $25 for Puerto Vallarta–Tepic, for example), passengers enjoy rapid passage and airline-style amenities: plush reclining seats, a (usually) clean toilet, air-conditioning, onboard video, and an aisle attendant.
Although less luxurious, but for about two-thirds the price, first-class (primera clase) service is frequent and always includes reserved seating. Additionally, passengers enjoy soft reclining seats and air-conditioning (if it’s working). Besides regular stops at or near most towns and villages en route, first-class bus drivers, if requested, will usually stop and let you off anywhere along the road.
Second-class (clase ordinario) seating is unreserved. In outlying parts of the Puerto Vallarta region, there is even a class of bus beneath second class, but given the condition of many second-class buses, it seems as if third-class buses wouldn’t run at all. Such buses are the stuff of travelers’ legends: The recycled old GMC, Ford, and Dodge schoolbuses that stop everywhere and carry everyone and everything to even the smallest villages tucked away in the far mountains. As long as there is any kind of a road, the bus will most likely go there.
Now and then you’ll read a newspaper story of a country bus that went over a cliff somewhere in Mexico, killing the driver and a dozen unfortunate souls. The same newspapers, however, never bother to mention the half-million safe passengers for whom the same bus provided trips during its 15 years of service before the accident.
Second-class buses are not for travelers with weak knees or stomachs. Often, you will initially have to stand, cramped in the aisle, in a crowd of campesinos. They are warm-hearted but poor people, so don’t tempt them with open, dangling purses or wallets bulging in back pockets. Stow your money safely away. After a while, you will be able to sit down. Such privilege, however, comes with obligation, such as holding an old woman’s bulging bag of carrots or a toddler on your lap. But if you accept your burden with humor and equanimity, who knows what favors and blessings may flow to you in return.
Mexican bus lines do not usually publish schedules or fares. Simply ask someone who knows (such as your hotel desk clerk), or call (or ask someone to call) the bus station. Few travel agents handle bus tickets. If you don’t want to spend the time to get a reserved ticket yourself, hire someone trustworthy to do it for you. Another option is to get to the bus station early enough on your traveling day to ensure that you’ll get a bus to your destination.
Although some lines accept credit cards and issue computer-printed tickets at their major stations, most reserved bus tickets are sold for cash and are handwritten, with a specific seat number (número de asiento) on the back. If you miss the bus, you lose your money. Furthermore, airline-style automated reservations systems have not yet arrived at many Mexican bus stations. Consequently, you can generally buy reserved tickets only at the local departure (salida local) station. (An agent in Puerto Vallarta, for example, may not be able to reserve you a ticket on a bus that originates in Tepic, 100 miles up the road.)
Request a reserved seat, if possible, with numbers 1–25 in the front (delante) to middle (medio) of the bus. The rear seats are often occupied by smokers, drunks, and rowdies. At night, you will sleep better on the right side (lado derecho), away from the glare of oncoming traffic lights.
Baggage is generally secure on Mexican buses. Label it, however. Overhead racks are generally too cramped to accommodate airline-sized carry-ons. Carry a small bag with your money and irreplaceables on your person; pack clothes and less-essentials in your checked luggage. For peace of mind, watch the handler put your checked baggage on the bus and watch to make sure it is not mistakenly taken off the bus at intermediate stops.
If your baggage gets misplaced, remain calm. Bus employees are generally competent and conscientious. If you are patient, recovering your luggage will become a matter of honor for many of them. Baggage handlers are at the bottom of the pay scale; a tip for their mostly thankless job is very much appreciated.
On long trips, carry food, beverages, and toilet paper. Station food may be dubious, and the sanitary facilities may be ill-maintained.
If you are waiting for a first-class bus at an intermediate salida de paso (passing station), you have to trust to luck that there will be an empty seat. If not, your best option may be to ride a more frequent second-class bus.