Assuming you’re referring to Puerto Viejo de Talamanca on the Caribbean Coast (and not Puerto Viejo de Sarapiqui located inland), the drive from San Jose is a little long but not bad. It’s about 4 hours along mostly highway. Getting out of San Jose is the most confusing part of the trip, so we definitely recommend getting a GPS or having a maps feature enabled on your smart phone. The Waze App also works really well in Costa Rica. Once you get out of San Jose, you drive along a mountainous highway where there can be some truck traffic, but once you reach the coast, it’s an easy drive south to Puerto Viejo.
If you haven’t already, be sure to check out our rental car discount to see if you can save some money on a car. Our discount usually works out to between 10-25% off and the company we work with is really reliable. There’s more info here: https://www.twoweeksincostarica.com/costa-rica-rental-car-discount/