Flying from the northeast? Consider looking at flights from Newark International Airport (EWR). They may be a lot cheaper than Philadelphia. If flying from Newark, and you want to save a little cash but have your car safe, then 'Economy Parking P6' is your lot. It is run by the airport, affordable, and has free bus service to the terminals. It takes like 20 minutes.
On your return flight, consider taking a redeye. There are some direct redeyes from PV (mostly to Newark), others will have you fly to the states and have a layover before the red eye. If you do the later, be sure to look at the layover time, and take off time of the second flight to ensure it is, in fact a red eye. Otherwise, you'll be sleeping in the airport! Why redeyes, you ask? Well, it gives you nearly another full day in sunny Mexico, which is great. But even better is that since you are flying West to East, you take off in the evening in Mexico and arrive in the morning on the East Coast. You can sleep on the flight and this syncs you up timewise (you fall asleep when you should and wake up when you should) and helps with jetlag.
Pack more sunscreen than you anticipate. Resorts are notorious for raising the price and no one wants to spend upwards of up to $50 USD on one can of spray.
Bring a sandwich ziplock baggie on the flight. You can put your phone in it and use the tray table latch to have it at eye level for movie viewing.
For whichever airline you are flying, be sure to download their app to your phone. Most airlines don't have TVs in the seats anymore. Instead, all the in-flight entertainment is accessible through their app, but you can only download it before the flight.
On exiting the airport, do not get lured in to speaking to one of the timeshare agents. They will try to trick you into thinking they are your transportation. Walk straight past them (they are indoors) and proceed to the transit area outdoors for your hotel transportation.
Going on an organized tour? There is likely going to be a photographer. Go ahead and get lots of photos taken. At the end of the tour do not buy them on the first go around. Instead, wait until pretty close to the end of the tour. They may come back around and offer a significantly lower price. If they don't come back around, you can go up to them and try negotiating. On our first tour (the ziplining), we paid like $90 for the photos. On our second tour (the Yelapa tour), we decided not to buy the photos, but towards the end of the boat ride, the photographer offered us the photos for like $40.
Best approach is to just ignore them. It may feel rude, and you may want to try to politely decline, but politeness is an 'in' for them to keep trying so just ignore them! You know the folks we are talking about, these are the people selling trinkets and stuff. You will find them on the boardwalk, and on the public beaches, sometimes outside of restaurants. They are all friendly and harmless, but they are quite aggressive in their tactics to get your attention and get a sale. This includes standard things like asking you to take a look, and loudly announcing what they are selling. One of the more sly tactics they use is to say a friendly 'yoo-hoo' in a high pitch to get you to look over. It may be fun the first few times, but gets old fast. Don't give a long winded explanation of why you aren't interested, just curtly say no thank you, avoid eye contact, and keep walking. Or ignore them all together.
Puerto Vallarta is a very safe town, but you are still in a different country and should respect their culture and norms. For you late night partiers, this includes not using a dark alley as your bathroom! A fake police officer may, or may not have tried to fleece down Dan for peeing on a desolate street at 2AM. We cannot confirm or deny this! :-)