Bus 12 links Plaza Libertad with the Cuevas de Bellamar and the Iglesia de Monserrate.
The Oro Negro gas station is 4km outside central Matanzas on the Varadero road. If you're driving to Varadero, you will pay a CUC$2 highway toll between Boca de Camarioca and Santa Marta (no toll between Matanzas and the airport).
Bici-taxis congregate next to the Mercado la Plaza and can take you to most of the city's destinations for one to two Cuban pesos. A taxi to Juan Gualberto Gómez International Airport should cost CUC$25 to CUC$30 (20 minutes), with Varadero fares (CUC$30; 40 minutes) a bit more again.