If you are relying on public transportation in the Zancudo / Pavones area, you will have very few options. There are private taxis that will take you just about anywhere but all rides are very expensive. Taxis average $50 USD to go between Golfito or Paso Canoas and Zancudo, and $50 - $70 to Pavones.
The big pink, green, or orange Tracopa buses will get you into the general area, you can hire a private boat between Golfito and Zancudo (Coco no longer runs the daily water taxi), a few public buses that run in the area, and some shared taxis to get you between those buses and Paso Canoas.
I have created a very rudimentary map to give you the lay of the land and the current bus routes.Transportes Barrantes Facebook page shows (most of) the times for the buses around that area but it's missing the Langostino to Neily at 1 pm. Check their home page too for special schedules.
Transportes Barrantes Schedule at time of writing:
Punta Banco-Golfito 5:30 a.m.
Pavones-Golfito 12:30 p.m.
Golfito-Pavones 10:00am y 3:00p.m.
La Esperanza-Ciudad Neily 5:15 a.m.
Zancudo-Ciudad Neily 5:30 a.m.
Ciudad Neily-Langostino 9:30 a.m.
Ciudad Neily-Zancudo 2:15 p.m.
Langostino-Ciudad Neily 1:00 p.m.
Just stand along the road in the towns along their route and flag the bus down when it goes by. Try to be on the road a little early since they don't have a very strict schedule. It all depends on road conditions and how many times they stop to pick people up. For instance, if you are in Pavones near the supermarket (Super Rio Claro) and want to catch the early bus to get to the border, be on the road by 5:45 even though you might be waiting until 6:00.
I'm lacking a bit on what time the busses hit Conte on their way to Zancudo or Pavones. That's key because if you are in Paso Canoas (a popular stop), you will need to time your shared taxi to when the bus comes through. For the Neily - Zancudo bus, the bus that leaves Neily at 2:15 pm, hits Laurel around 4pm next to Megasuper and gets into Zancudo around 5:30pm+. I do see the bus coming into town at around 5:35pm each evening.
Paso CanoasPaos Conoas is a popular town for either passing through on your way in and out of this area or for going shopping. There's a free zone (you don't have to go through immigration) in Panama with tons of departments stores and liquor stores and is a good place to stock up on things that may not be dirt cheap, but they're cheaper than Costa Rica.
To get to and from Paso Canoas and the beach towns, you use a shared colectivo taxi to shuttle you between Paso Canoas and the bus stop towns of either Laurel or Comte. Either town is fine, it's just a matter of spending more or less time/money on the slow bus that will take you to the beach (Laurel is further from the beach towns but closer to Paso Canoas).
A shared taxi between Paso Canoas and Laurel should cost ₡1,000 (about $1.75) and takes about half an hour. If coming from Paos Canoas, you'll then get the Neily bus as it comes through at 3 pm on its way to Zancudo for around ₡1,600. The ride takes at least an hour and the bus will drop you off anywhere on the road that you ask. A colectivo between Paso Canoas and Comte costs ₡2,500 (45 min.).
You can find the colectivo taxis in Laurel and Comte waiting where the bus stops. In Paso Canoas, you'll see tons of them near the border. The taxis will be more than willing to take you in a private taxi (for something like $30 USD!) so make sure you specify colectivo . Hopefully there is anther person going the same way so you’ll share the ride with them (I don’t think the taxi will go if there’s only one person) and your driver will try to pick up additional people along the way.
ZancudoLike Pavones, there are limited bus options. There's one bus per day that leaves Zancudo at 5am, goes to Ciudad Neily by way of Comte and Laurel, and returns in the evening. There are a few other straggler routes in neighboring towns (for instance you'd have to get someone to drive you to Langostino to get the bus from there), but that Zancudo - Neily bus is your go-to. But Zancudo has the added bonus of the boat to and from Golfito.private boat for $60.
The public bus between Golfito and Rio Claro costs about $1 (1/2 hour). You pay the driver when you get on. If going to Golfito, ask him to let you off at the muellecito (the small public pier). It's across the street from the Supermercado Pearson and next to Hotel Golfito.
If you end up in Golfito with no boat to take, it's not impossible to take a bus to Zancudo. There's a 10:00 am and a 3 pm bus to Pavones that says "Pavones/Comte" on the front. Just stand on the main road and flag it down when it goes by. In front of the Chino market and at the dock are popular places to catch it. Take the morning bus to Langostino and arrange a ride from there or take the later bus all the way to Zancudo. Ask the driver since you might have to get off early in Comte where a bus will come by on it's way from Ciudad Neily going to Zancudo. Zancudo - A Challenge Getting There and Away and Getting To and From Pavones Surf Town on a Budget. There's information on Zancudo and Paso Canoas and photos on some of the different stops.
Private Car HiresLuis (+506 8396-0243) - based in San Jose
Walter (+506 8847-6026) - based in San Jose
Sonny (+1 441-705-5555) - based in Zancudo
Boat CaptainsPeter (via Facebook) (I don't have his phone number)
Nelson (+506 8575-0095)
Coco (Eric) (+506 8638-7712)