It's certainly a great way to discover the Peninsula of Azuero by car. Renting one during your stay in Panama will give you the ability to do some great exploring of Playa Venao as well as the surrounding beaches.
If you come from Tocumen Airport take the freeway to the city (corredor sur). Leave the city over the Bridge of the Americas (puente de las americas). map
Just before Divisa there are billboards advertising the town and the coast of Pedasi, that’s where you want to be heading. There will be a turnoff to the right, with a small bridge veering to the left, (in a curve above the highway) and then down towards the towns of Chitre, Las Tablas, Pedasiand finally, at pretty much the end of the road, Playa Venao.
It might be smart to have a closer look at the map around the towns of Chitre and Las Tablas – so you can get an idea of where the by-passes are and where to go in case you miss them and end up driving through town.
Note: the last petrol-station is in Pedasi – about~30km before Playa Venao.